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{/Home --
Basic Introduction of GFP
A: Ever heard of GFP? I’m so glad of its existence!
B: Huh? What is GFP? Is it an acronym for a poplar online game or a book?
A: *shows lame face* Oh, unfortunately, I might have to disappoint you. Instead, GFP stands for Green Fluorescence Protein.
B: Green fluorescence protein? What does it do? Does it really glow? Who discovered it? How does it benefit us?
A: WAIT!!! Not so many questions at once. Frankly speaking, I do not know too. Perhaps, visiting here will help?
B: Huh? What is GFP? Is it an acronym for a poplar online game or a book?
A: *shows lame face* Oh, unfortunately, I might have to disappoint you. Instead, GFP stands for Green Fluorescence Protein.
B: Green fluorescence protein? What does it do? Does it really glow? Who discovered it? How does it benefit us?
A: WAIT!!! Not so many questions at once. Frankly speaking, I do not know too. Perhaps, visiting here will help?
Group Introduction
Welcome! We are group of students from Nanyang Girls' High School, Singapore. This webpage was designed for our participation in the Chemistry Communication Competition 2009. Our chosen topic is Green Fluorescent Protein.
Do support us in our quest for knowledge! :D
Introduction to GFP
Structure of GFP
Maturation of GFP
Modifications to GFP: Green; Yellow; Blue; Orange;
History & Timeline of GFP
The Green Fluorescent Protein(GFP) is found in a type of jellyfish, Aequorea Victoria, and can be traced back to more than one hundred and sixty million years. It was first described by Osamu Shimomura and has been researched on and further developed by many scientists, most recognisably Marty Chalfie and Roger Tsien, since it was cloned. Thereafter, it has been used by scientists in various fields of scientific research, especially as a tracer molecule. To date, the GFP gene has been introduced and expressed in many bacteria, yeast and other fungi, plant, fly, and mammalian cells, including human. The significance of GFP was recognised when in 2008, Osamu Shimomura, Marty Chalfie and Roger Tsien shared the Nobel Prize in Chemistry "for the discovery and development of the green fluorescent protein, GFP." Although they did not share the 2008 Nobel Prize in Chemistry, Douglas Prasher and Sergey Lukyanov are also recognised as major contributors to the research on GFP.
Image above shows jellyfish, Aequorea Victoria.
Ever wondered how the protein glows?
Firstly, the structure of a GFP has a unique soda can shape. Eleven beta strands make up a beta-barrel, and a beta-sheet with alpha-helix runs through the center. A chromophore, which refers to a chemical group that is capable of selective light absorption resulting in the coloration of certain chemical compounds, is located in the middle of the beta-barrel. Figure 1 is an illustration of this protein.
The blue strands represent the 11 beta strands, while the green “thing” in the center is the β-sheet with alpha-helix which contains the chromophore.
However, what is the cause of the fluorescence properties in the chromophore?
It is derived from a triplet of adjacent amino acids, namely the serine, tyrosine, and glycine which residues at locations 65, 66, and 67 respectively, which are otherwise known as Ser65, Tyr66, and Gly67. However, even though this simple amino acid motif is commonly found throughout nature and other organisms, it does not always result in fluorescence. The uniqueness of the GFP lies in the location of this peptide triplet. Besides its unique position in the alpha helix, the chromophore is not always stable. Thus, it has to undergo a series of changes before it can fluoresce.
It is derived from a triplet of adjacent amino acids, namely the serine, tyrosine, and glycine which residues at locations 65, 66, and 67 respectively, which are otherwise known as Ser65, Tyr66, and Gly67. However, even though this simple amino acid motif is commonly found throughout nature and other organisms, it does not always result in fluorescence. The uniqueness of the GFP lies in the location of this peptide triplet. Besides its unique position in the alpha helix, the chromophore is not always stable. Thus, it has to undergo a series of changes before it can fluoresce.
The marked-on portions are serine and part of tyrosine respectively. They undergo folding, leading to an imidazolinone formation.
Then, in the blue highlighted area, the Hydrogen in NH binds to Oxygen in cyclization.
However up till this stage, the GFP still does not fluoresce. It then continues to undergo dehydration. OH and also Hydrogen is removed from NH, resulting in a double carbon bond.
Lastly, it will undergo aerial oxidation, and oxygen is removed, resulting in a double carbon bond as seen in this animation. The chromophore is now able to fluoresce.
The image on the left shows the structure before it undergoes maturation. The image on the right has undergone maturation.
Furthermore, the entire 27 kiloDalton native peptide structure in the green fluorescent protein is
essential to the development and maintenance of its fluorescence.
Green Fluorescent Protein
In a normal GFP, in the presence of ultraviolet light, it will fluorescence green, which has a wavelength of about 480. However, the colour of the fluorescence can be changed by modifying the structural formula of the protein. That is, the arrangement of the amino acids is changed as amino acids are removed or added, depending on the colour which should be obtained.
Yellow Fluorescent Protein
To obtain a yellow colour, mutations of threonine203 (Thr203) is introduced to tyrosine (Tyr66). This results in a 20 to 30-nanometer shift in wavelength as yellow has a wavelength of approximately 510. Further refinements to this protein produces enhanced yellow fluorescent protein (EFYP) which is one of the brightest and most widely used fluorescent proteins as such qualities make it an excellent candidate for multi-colour imaging experiments in fluorescence microscopy. However, a down side of the yellow fluorescent protein is that it is very sensitive to acidic pH and loses approximately 50 percent of is fluorescent at pH 6.5
Blue Fluorescent Protein
To obtain this colour, conversion of tyrosine66 (tyr66) to histidine results in a blue fluorescence, wavelength of 380 nanometers.
Orange Fluorescent Protein
Orange fluorescent protein has a wavelength of 550 nanometers
Hope you've enjoyed this animation we made. :)
In a normal GFP, in the presence of ultraviolet light, it will fluorescence green, which has a wavelength of about 480. However, the colour of the fluorescence can be changed by modifying the structural formula of the protein. That is, the arrangement of the amino acids is changed as amino acids are removed or added, depending on the colour which should be obtained.
Yellow Fluorescent Protein
To obtain a yellow colour, mutations of threonine203 (Thr203) is introduced to tyrosine (Tyr66). This results in a 20 to 30-nanometer shift in wavelength as yellow has a wavelength of approximately 510. Further refinements to this protein produces enhanced yellow fluorescent protein (EFYP) which is one of the brightest and most widely used fluorescent proteins as such qualities make it an excellent candidate for multi-colour imaging experiments in fluorescence microscopy. However, a down side of the yellow fluorescent protein is that it is very sensitive to acidic pH and loses approximately 50 percent of is fluorescent at pH 6.5
Blue Fluorescent Protein
To obtain this colour, conversion of tyrosine66 (tyr66) to histidine results in a blue fluorescence, wavelength of 380 nanometers.
Orange Fluorescent Protein
Orange fluorescent protein has a wavelength of 550 nanometers
Hope you've enjoyed this animation we made. :)
1955 - Green fluorescent substance in jellyfish first described.
1962 - GFP identified as protein, extracted from 10,000 jellyfish -
"a protein giving solutions that look slightly greenish in sunlight though only yellowish under tungsten lights,
and exhibiting a very bright, greenish fluorescence in the ultraviolet of a Mineralite, has also been isolated
from squeezates." Called "green protein." 1969 - "Green protein" named green fluorescent protein.
1974 - Intermolecular energy transfer between aequorin and GFP in jellyfish and when co-absorbed on Sephadex column. See Figure below.
1979 - Shimomura characterized structure of chromophore
1985 - Prasher clones and expresses aequorin.
1992 - GFP cloned
1993 - Structure of GFP chromophore confirmed, flanking amino acid residues corrected from Shimomura's 1979 structure.
1994 - GFP expressed in E. coli (10,11) and C. elegans. Mechanism for chromophore formation. First new color (blue) and oxygen dependence reported. Possibility of use in FRET experiments mentioned.
1995 - The origin of enhanced GFP (EGFP).
1996 - First crystal structures of wild-type and enhanced GFP. Tsien designed T203Y mutant based on crystal structure of S65T GFP. It is yellow fluorescent.
1997 - Photoisomerization between A(neutral) and B(anionic) forms of wild-type GFP elucidated.
1999 - Red fluorescent proteins (DsRed) discovered in anthozoan corals. Leads to discovery of many new fluorescent proteins and chromoproteins. GFP tolerates insertion of entire proteins in certain locations and can be circularly permuted.
2000 - Fluorescent timer protein
2002 - Monomeric DsRed (mRFP), first photoconverible (Kaede), and photoactivatable (PA-GFP) FPs created
2003 - Kindling protein (KFP) can undergo irreversible photoconversion from non-fluorescent to stable red fluorescent form upon photoactivation
2004 - New "fruit" FPs generated by in vitro and in vivo directed evolution
2007 - mKate, bright far-red FP. FP found in amphioxus, first time in chordates. Molecular thermometer based on FP blinking.Latest GFP review
2008 - The first mutant of the Aequorea victoria GFP that forms a red chromophore reported.
Nobel Prize
Osamu Shimomura
Marty Chalfie
Roger Tsien
Douglas Prasher
Sergey A. Lukyanov
In October 2008, Shimomura, Chalfie and Tsien shared the 2008 Nobel Prize in Chemistry for
the discovery and development of the green fluorescent protein, GFP. Although Prasher and
Lukyanov did not share the prize, their contributions have been recognised by the scientific society.
Born on 27 August in 1928, Shimomura faced challenges in furthering his education in post-war Japan.
He enrolled in the College of Pharmaceutical Sciences of Nagasaki Medical College and later earned a
Bachelor of Science degree in pharmacy in 1951. Thereafter, he continued to be a lab assistant at the
school and was then employed as an assistant to Professor Yashimasa Hirata at Nagoya University in
1955. While working for Professor Hirata, he successfully discovered what made the remains of a
crushed mollusc, Cypridina, glow when it was moistened with water in 1956 as tasked by the professor
and also earned a Master of Science degree in organic chemistry in 1958. Professor Frank Johnson of
the University of Princeton then recruited him in 1960 when he also gained a Ph.D. in organic chemistry
at Nagoya University. He is married to Akemi Shimomura with a son, Tsutomo Shimomura, and daughter,
Sachi Shimomura.
Born 15 January 1947, Chalfie entered Harvard University in 1965 and graduated in 1969.
He later went on to receive a Ph.D. in neurobiology at Harvard in 1977. He then joined
the faculty of biological sciences at Columbia University and became the William R. Kenan,
Jr. Professor and also chairman of the department. At Columbia University, he also continued
his research on C. elegans, a type of transparent free-moving roundworm. He was elected to
the National Academy of Sciences in 2004 and is married to Tulle Hazelrigg.
Born on 1 February 1952, Tsien used to conduct his own experiments at home as he was kept
indoors due to asthma. He later studied at Harvard University and graduated in 1972 with
a Bachelor of Science in both chemistry and physics. After which, he graduated from the
University of Cambridge with a Ph.D. in Physiology in 1977.
Little known is Prasher’s contribution towards the development of the GFP as he was not
included in the Nobel Prize. Born in August 1951, Prasher obtained his Ph.D. in biochemistry
in 1979 at Ohio University and was later funded to clone the gene for the GFP. He later on
shared his findings with the other two Nobel Laureates, Marty Chalfie and Roger Tsien which
contributed much towards the their research. Henceforth, he worked for the US Department of
Agriculture as a population geneticist. And although he did not share the Nobel Prize, he was
acknowledged by all three Laureates in their Nobel speech.
Another major contributor to research on the GFP, Lukyanov, was born in 13 September 1963,
and is the Head of the Laboratory of Molecular Technologies at the Russian Academy of Sciences.
There, he also received his Ph.D. in 1994 and D.Sc. in 1999. He is also the corresponding member
of the Russian Academy of Sciences.
Impact
GFP in Brainbow
HIV Virulence
Watching Mice think
Neural Growth
Malaria
Cancer
Controversies
Transgenic Pets
Cloned Pigs
{/iMPACT of Discovery of GFP --
GFP in Brainbow
Never before has a brain been so beautiful. Jeff Lichtman and Joshua Sanes, researchers at the Harvard Brain Center,
have created transgenic mice with fluorescent multicolored neurons. The photographs of the mouse brains that appear
in the November 1, 2007 issue of Nature could be housed in the Museum of Modern Art or could be used to decorate
Joseph's technicolored dream coat. But it is not their colorful splendor that makes these genetically modified mice
so amazing. It is their potential to revolutionize neurobiology that excites scientists like myself and has our
neurons firing away, creating oodles of endorphins.
The mice created by a genetic strategy termed "brainbow" will have a similar effect on neuroscience as Google Earth had on cartography. Using a brainbow of colors, researchers will now be able to map the neural circuits of the brain. The individually colored neurons will help define the complex tangle of neurons that comprise the brain and nervous system. By creating a wiring diagram of the brain, researchers hope to help identify the defective wiring found in neurodegenerative diseases such as Altzheimer's and Parkinson's disease.
In the Brainbow mice, the Harvard researchers have introduced genetic machinery that randomly mixes green, cyan and yellow fluorescent proteins in individual neurons thereby creating a palette of ninety distinctive hues and colors. "The technique drives the cell to switch on fluorescent protein genes in neurons more or less at random," says Jean Livet, the postdoctoral researcher responsible for most of the laboratory work that resulted in the Brainbow mice.
The mice created by a genetic strategy termed "brainbow" will have a similar effect on neuroscience as Google Earth had on cartography. Using a brainbow of colors, researchers will now be able to map the neural circuits of the brain. The individually colored neurons will help define the complex tangle of neurons that comprise the brain and nervous system. By creating a wiring diagram of the brain, researchers hope to help identify the defective wiring found in neurodegenerative diseases such as Altzheimer's and Parkinson's disease.
In the Brainbow mice, the Harvard researchers have introduced genetic machinery that randomly mixes green, cyan and yellow fluorescent proteins in individual neurons thereby creating a palette of ninety distinctive hues and colors. "The technique drives the cell to switch on fluorescent protein genes in neurons more or less at random," says Jean Livet, the postdoctoral researcher responsible for most of the laboratory work that resulted in the Brainbow mice.
This is a photograph of the cerebral cortex. It's hard to believe, but in non-living preserved brains, the outerlayers of this portion of the brain are gray, which is why the brain is sometimes called "gray matter".
Another image of the cerebral cortex, which plays an important role in memory, perceptual awareness, thought and language.
On this confocal microscopy image from the brain stem, tube-like structures are axons of the auditory
pathway, which are forming hand-shaped synapses on other neurons (here unlabeled).
HIV Virulence
When human T-cells bump into each they form a sticky strand that connects the two cells. These strands
dubbed "membrane nanotubes" by the Imperial College scientists who discovered them can connect two
T-cells that are several cell lengths apart. By infecting a T-cell with HIV containing GFP labelled
proteins the researchers were able to show that HIV proteins travel down the nanotubes from infected
to non-infected cells. These nanotubes maybe part of the reason HIV is so effective at spreading rapidly
within host bodies.
Time-lapse imaging of GFP tagged proteins moving along a membrane nanotube connecting infected
with uninfected T cells. The boxed regions in are enlarged to show that the protein-GFP reaches the
initially uninfected T cell.
Watching Mice Think
Karel Svoboda at the Cold Spring Harbor Laboratories on Long Island is doing something no one else has ever done before.
He is watching how mice think. He doesnt sit and watch a mouse in a maze with a puzzled expression on its face no,
he watches the brain of a mouse react to new experiences. How does he do this? With GFP of course. Joshua Sanes, a
collaborator of his from the Washington University School of Medicine in St. Louis, created a transgenic mouse strain
that expresses GFP in some of the neurons in the cortex. Then together with some of his students and collaborators,
Svoboda has replaced sections of the skulls of these transgenic young mice with transparent windows, so that they can
watch what happens to the region of their cortices, which processes sensory information derived from their whiskers.
The mice can live out their entire lives with the windows in place, allowing Svoboda the opportunity to monitor the
changes occurring over many weeks. He observed tiny spines along the dendrites rising and receding. The rate of spine
turnover increased as the mice were exposed to new experiences. Figure 7 shows YFP and GFP labeled cerebral neurons in
two lines of transgenically modified mice. Karel is now continuing his work at the HHMI Janelia Farm.
Fluorescent protein expression in the cerebral neurons in two different lines of transgenic mice. In the one line,
GFP is expressed sparsely; in the other YFP is expressed abundantly. Both pictures were taken through a glass window
embedded in live mice.
Using similar methods Kuan Hong Wang, a researcher at MIT's Picower Institute for Learning and Memory, was able to monitor protein expression in the primary visual cortex of living mice. He and his co-workers labeled a protein named, ARC, which acts as a molecular filter enhancing the brains ability to respond to visual stimuli. In a study reported in Cell 2006, 126, pg. 329 they examined the expression of ARC in the brain of mice that were exposed to cylinders with vertical and horizontal stripes. They found that if they repeatedly exposed the infant mice to the same visual stimulus the amount of ARC produced decreased. The Arc protein was training the brain to interpret the visual signals. One of the ways it does this is by blocking the activity of less efficient neurons.
Using similar methods Kuan Hong Wang, a researcher at MIT's Picower Institute for Learning and Memory, was able to monitor protein expression in the primary visual cortex of living mice. He and his co-workers labeled a protein named, ARC, which acts as a molecular filter enhancing the brains ability to respond to visual stimuli. In a study reported in Cell 2006, 126, pg. 329 they examined the expression of ARC in the brain of mice that were exposed to cylinders with vertical and horizontal stripes. They found that if they repeatedly exposed the infant mice to the same visual stimulus the amount of ARC produced decreased. The Arc protein was training the brain to interpret the visual signals. One of the ways it does this is by blocking the activity of less efficient neurons.
Neural Growth
Jeff Lichtman and his co-workers have created a series of transgenic mice that express fluorescent proteins in their
neurons. By mating a female expressing blue fluorescent protein in her neurons with a male expressing GFP they could
watch differently colored neurons competing for the muscle surface in their offspring, see below.
A mouse with different neuron colors inherited from its two parents can reveal how neurons network in the brain.
Malaria
Malaria is the world's most common and deadly parasitic disease. The World Health Organization estimates that each year 300-500 million cases of malaria occur and more than 1 million people die of malaria. A possible breakthrough in curtailing the spread of malaria carrying mosquitoes was reported in October 2005 the creation of mosquitoes with green fluorescent testicles. Now male mosquito larvae (see picture above) can easily be separated from female mosquito larvae. Without green fluorescent gonads it is impossible to separate mosquito larvae based on their sex, and it is very difficult to separate the adults since they fly about and bite (actually only the females bite). Now a laser sorting machine has been developed that can sort 180,000 larvae in 10 hours. Once separated from the females it is trivial to sterilize the males and release them into the environment where they will mate with wild females. Female mosquitoes only mate once in their two-week cycle, so if they chose a sterilized male they will produce no offspring. If a large enough population of sterilized males is released into the wild population should be eradicated in a fairly short time.
Cancer
Anticancer Inc. have developed a nude transgenic mouse, see pictures below.
Mouse under blue light (top) Same mouse under normal light (bottom)
When a blue light is shone on the mouse every cell (that contains actin) in its body will fluoresce green. Human cancers that express DsRed can be implanted into these mice. The cancers will give off red fluorescence. Now the cancer cells can easily be observed and monitored in live green mice. Allowing the researchers at Anticancer Inc. to observe metastasis (cancer cells moving around the body) and angiogenesis (blood vessels growing into the cancer and supplying oxygen and food).
When a blue light is shone on the mouse every cell (that contains actin) in its body will fluoresce green. Human cancers that express DsRed can be implanted into these mice. The cancers will give off red fluorescence. Now the cancer cells can easily be observed and monitored in live green mice. Allowing the researchers at Anticancer Inc. to observe metastasis (cancer cells moving around the body) and angiogenesis (blood vessels growing into the cancer and supplying oxygen and food).
Mouse blood vessels (green-GFP) in tumor (red-DsRed). Mouse with brain tumor expressing DsRed.
{/cONTROVERSIES of Discovery of GFP --
lba, a fluorescent rabbit, was commissioned by Eduardo Kac using GFP for purposes of art and social commentary,
and was created by French genetic researchers. Alba is a cuddly albino rabbit that hops around, snuffles its nose,
and munches carrots just like any other rabbit. Turn off the lights, switch on the ultra violet lamps and it becomes
GFP Bunny, a transgenic artwork, changing from loveable family pet to a disconcerting vision of the future, a science
fiction pet with an eerie green glow emanating from every cell, from her paws, her whiskers, and especially her eyes.
The French scientists created Alba using a process called zygote microinjection. In this process, the scientists plucked
a fluorescent protein from a species of fluorescent jellyfish called Aequorea victoria. Then they modified the gene to
make its glowing properties twice as powerful. This gene, called EGFG (for enhanced green fluorescent gene) was then
inserted into a fertilized rabbit egg cell that eventually grew into Alba. As the cell divided, the “green gene” also
replicated and made its way into every cell of Alba’s body
Kac had wanted Alba to highlight the fact that transgenic animals are regular creatures that are as much part of social life
as any other life form. He had intended for Alba’s birth in February to spark a debate about the project itself, and about
the practice of manipulating genes in animals for research. Then he hoped to adopt Alba and take her into his home with his
wife and daughter. Kac says the entire project, is designed to combine biotechnology, private family life and the social
domain of public opinion into a single furry symbol. But so far, it seems Kac’s first objective has overshadowed the others.
Scientists at the National Institute of Agronomic Research in France, which created the rabbit for Kac, are hesitating to
release the rabbit to him and his family due to protests over its creation. Kac and Alba were going to live in a faux living
room created in the gallery, signifying how biotechnologies are entering our lives, even in the privacy of our living rooms.
However, on the eve of the show the director of the institute who had created Alba reportedly refused to release her to Kac,
fuelling the dialogue portion of the exhibit. The GFP-Bunny exhibit was meant to be a political project that would break down
the barriers between art, science and politics, and in this it succeeded.
Animal rights activists claim the project is a needless and abusive manipulation of an animal, while scientists who work with the fluorescent proteins have dismissed the project as interesting but silly. “There’s nothing dangerous about it, as far as we know,” says Woodland Hastings, a biologist at Harvard University and co-discoverer of the jellyfish’s glowing gene and its function. “But the project is rather frivolous. There are many more important things you can do with these genes.” However, at least, such a project gives people in the public a chance to react to what is going on in the scientific community, as it is important to bring what people in white coats do into the public forum.
This isn’t the first time a mammal has been designed to glow. In 1997 Tokyo scientists added glowing jellyfish genes to mice. The mice, however, were created for research purposes — to provide animal models for studying biological processes and diseases. As Hasting explains, the luminescent jellyfish genes can be used to tag certain genes or proteins. When that protein is active, scientists can detect its fluorescence under a black light. When it’s inactive, no fluorescence appears. That kind of tracing ability allows scientists to watch the effectiveness of potential drugs as they affect the body without using surgery. For example, anti-cancer genes can be inserted with the glowing genes so a light source is all that is needed to learn if genetic manipulation is successful. Hasting adds that in the future the technology may also help guide surgeons as they cut away cancerous genes during surgery. “If you can make a particular gene glow, then you should be able to see when and where a cancer cells is,” he says. “That can localize the cancer and help the surgeon know where to cut.” Osamu Shimomura, a biologist at Woods Hole Marine Biological Laboratory and one of the first to detect the glowing gene in Aequorea victoria, is now working on developing variations of the gene for disease research.
Astonishingly, there are variations of the jellyfish’s glowing genes surfacing that have been used in another relatively non-scientific application. In December, a company called Prolume began marketing squirt guns loaded with replicated versions of the genes. The liquid squirts like water, but lights up when it comes in contact with a person, or any substance containing calcium. Other researchers are working on developing glow-in-the-dark hair mousse, ink and cake frosting. There is even preliminary research underway to produce glow-in-the-dark beer and champagne. Still, Lisa Lange, the director of policy and communications at People for the Ethical Treatment of Animals, points out these other applications of glow genes don’t take advantage of an animal’s life, unlike certain experiments such as Kac’s.
Animal rights activists claim the project is a needless and abusive manipulation of an animal, while scientists who work with the fluorescent proteins have dismissed the project as interesting but silly. “There’s nothing dangerous about it, as far as we know,” says Woodland Hastings, a biologist at Harvard University and co-discoverer of the jellyfish’s glowing gene and its function. “But the project is rather frivolous. There are many more important things you can do with these genes.” However, at least, such a project gives people in the public a chance to react to what is going on in the scientific community, as it is important to bring what people in white coats do into the public forum.
This isn’t the first time a mammal has been designed to glow. In 1997 Tokyo scientists added glowing jellyfish genes to mice. The mice, however, were created for research purposes — to provide animal models for studying biological processes and diseases. As Hasting explains, the luminescent jellyfish genes can be used to tag certain genes or proteins. When that protein is active, scientists can detect its fluorescence under a black light. When it’s inactive, no fluorescence appears. That kind of tracing ability allows scientists to watch the effectiveness of potential drugs as they affect the body without using surgery. For example, anti-cancer genes can be inserted with the glowing genes so a light source is all that is needed to learn if genetic manipulation is successful. Hasting adds that in the future the technology may also help guide surgeons as they cut away cancerous genes during surgery. “If you can make a particular gene glow, then you should be able to see when and where a cancer cells is,” he says. “That can localize the cancer and help the surgeon know where to cut.” Osamu Shimomura, a biologist at Woods Hole Marine Biological Laboratory and one of the first to detect the glowing gene in Aequorea victoria, is now working on developing variations of the gene for disease research.
Astonishingly, there are variations of the jellyfish’s glowing genes surfacing that have been used in another relatively non-scientific application. In December, a company called Prolume began marketing squirt guns loaded with replicated versions of the genes. The liquid squirts like water, but lights up when it comes in contact with a person, or any substance containing calcium. Other researchers are working on developing glow-in-the-dark hair mousse, ink and cake frosting. There is even preliminary research underway to produce glow-in-the-dark beer and champagne. Still, Lisa Lange, the director of policy and communications at People for the Ethical Treatment of Animals, points out these other applications of glow genes don’t take advantage of an animal’s life, unlike certain experiments such as Kac’s.
Cloned Pigs
Randy Prather, a professor of reproductive biotechnology at the University of Missouri, Columbia, is one of the researchers
in the forefront of the creation of transgenic swine for medicine. He often uses GFP and its yellow mutant YFP as a marker
to show that foreign genes can be expressed in transgenic swine. The photo below shows two pigs, the one on the right is a
regular piglet, a little cleaner than your typical piglet, but no different from the piglets you find on a hog farm. The one
on the left is clearly very different to any pig we have ever seen before. It is a transgenic YFP cloned pig created by
Professor Prather. It was formed to show that it is possible to produce a transgenic clone. In the words of Prather: "These
animals prove that we can make genetic modifications to express desired traits. For xenotransplantation, this is a large
step because it means it's possible to change the genetic makeup of the cells to prevent the body's rejection of transplanted
organs." Sky News summed up the research in the following way: "Scientists have developed the first pig with a fluorescent
yellow snout and trotters using jellyfish DNA. Researchers in the US say the work is a step towards growing animal organs
for transplants - which could save thousands of human lives. But opponents have said the work is a freak show and a perversion of science."
Transgenic YFP piggy (left) and "normal" little piggy.
{/Acknowledgments & References --
Acknowledgements
We would like to acknowledge Mrs Lai Swee Choo and Mr Eric Tan for giving us an opportunity to participate in this competition and taking time off to guide us, ensuring we're on the right track.
References
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Blogskin Desginer DancingSheep
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http://www.microscopyu.com/articles/livecellimaging/fpintro.html
http://www.ekac.org/abc.html
http://www.conncoll.edu/ccacad/zimmer/GFP-ww/chalfie.html
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Questionnaire!
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