Oct 23, 2013 (3 years and 7 months ago)


Name: _______________________
_______________ Date: ________
_ Period: __


Go to the following site and complete the activity while answering the following questions:


What is the name of the gene that leads to the creation of the luciferase enzyme? Where is
it located?


Briefly describe how the LUC gene becomes a sequence of amino acids.


After transcription, but before translation, th
ere is a key step that takes place

it is skipped
in the animation. What occurs in the nucleus to the RNA before it leaves through a nuclear


What must happen to the string of amino acids before it is a “functioning luciferase
enzyme”? Why?


What must the luciferase do before it can generate visible light?


What do fireflies use this reaction for?


What do you think would happen if the LUC gene was put into the human genome? Or the
genome of a plant?


Read the article fro

from 1986
and answer the following

on the back or a separate sheet of
: Why was this “exciting” to the scientific community? What implications do you think it had
at the time for studying genetics?

Monday, Nov. 17, 1986

Science: Of Fireflies

and Tobacco Plants

By David Bjerklie/New York;MICHAEL D. LEMONICK

It sounds like a child's riddle: What do you get when you cross a firefly with a tobacco plant?
Answer: tobacco that lights itself. That is essentially what a team of scientists at the
University of
California at San Diego has done. By outfitting a fragment of a plant virus with the gene that tells
firefly cells to produce a protein central to generating light, the researchers have created a plant
that literally glows in the dark.

The t
echnique, reported in last week's issue of the journal Science, is significant not so much as a
demonstration of virtuoso genetic engineering, but because it will provide scientists with a
valuable research tool for studying how genes go about their busine
ss. By fusing the firefly gene to
the genetic material of other plants and animals, biologists gain a visual cue $ that will help them
understand in detail how genes

strands of DNA whose structure acts as a sort of coded instruction

tell diffe
rent cells what their duties are within an organism. Armed with such specific
knowledge, researchers may someday understand exactly why these instructions are occasionally
garbled and, perhaps, why cancer and other gene
influenced diseases occur. Predicts
Howell, a plant molecular biologist and a member of the research team: "The scientific community
will be able to exploit this tool for as many purposes as one can imagine."

In studying genes, scientists deal basically with two components: one part

supplies the code for the
production of a particular protein, and the other, a sort of regulatory switch, turns the protein
producing mechanism on and off. In the human body, as in all organisms, every cell contains the
complete genetic code and, in theor
y, has the potential to serve any function. A liver cell has the
instructions necessary to grow hair, for example, and a bone cell to transmit information as a nerve
does. The reason these things do not happen is that the instructions

the genes

are s
witched on
only under very specific conditions. If researchers can fuse the firefly gene to specific plant or
animal genes, they will be able to monitor the "expression," or turning on, of those genes simply by
looking at what parts of the organism light u
p, and when.

The initial impetus for the research came from a rather oblique direction. UCSD Biochemist
Marlene DeLuca has been investigating for 20 years how the firefly protein

in this case, an
enzyme called luciferase

produces light. But the proc
ess of collecting and grinding up fireflies to
extract the enzyme was laborious and costly. She and Donald Helinski, a molecular geneticist,
decided to isolate the luciferase gene, cloning exact copies of it and splicing it into the genetic
machinery of th
e common bacterium E. coli. The E. coli could then massproduce luciferase by the
vat. DeLuca and Helinski accomplished this task by using standard recombinant DNA techniques
developed over the past 20 years and now widely employed in industrial microbiolog
y laboratories.

The UCSD team quickly realized that the successful harnessing of luciferase might yield other
benefits. If the firefly gene was a simple, straightforward and easily manipulated one
enzyme system (some enzymes require the cooperativ
e efforts of several genes), it might be
possible to use it as a $ marker, or "reporter," gene. "We lucked out," says Helinski. "It did turn out
to be a single gene that we could manipulate."

They enlisted Howell and a colleague, David Ow, who began tryin
g to package the gene in a way
that could prove useful to the research of gene expression. The resulting procedure, though the
simplest available, might have been designed by Rube Goldberg. The luciferase gene was spliced to
the regulatory switch of a gene

belonging to a virus that infects plants. The altered two

part piece
of DNA was then inserted into a circular strand of DNA, called a plasmid, from the bacterium
Agrobacterium. The bacterial plasmid was incubated with tobacco
leaf cells, and the cells we
nurtured into full
fledged plants.

Why choose tobacco? Says Howell: "Tobacco is the laboratory rat of plant molecular biologists. It's a
model system that we use in these sorts of experiments." Responding to orders from the firefly
virus gene, the plan
ts dutifully produced their own luciferase.

The final step was to irrigate the plants with a solution containing luciferin, another substance
found in fireflies, which must combine with luciferase, oxygen and adenosine triphosphate, a
substance found in al
l cells, to produce the familiar luminescence. The plant's well
being is
unaffected by the glow, which can be seen only with sensitive video equipment, photographic time
exposures or eyes that have become accustomed to the dark.

Response from the scientifi
c community is already enthusiastic; labs in the U.S., Europe and Asia,
as well as several biotechnology companies, have requested samples of the tailored gene
containing the firefly
virus DNA for use in their own research. Another UCSD team has taken this

technique a step further, transferring the luciferase gene into monkey cells growing in laboratory

Howell expects little outcry from anti
engineering activists about the plant experiments'
danger to the environment. "At this time, this i
s only a laboratory creature. And plants don't fly or
crawl across the floor or creep into mouseholes. You can set one down and be pretty sure that's
where it's going to be when you look again."