Here is a new study which says that the brain developes in the womb over a long
period of time. The proteins in the brain are much more complex than the rest
of the cells in the body. This work was done in a much shorter time thanks to
the human genome project at NIH. More evidence that brain research must
continue.
Take care, Bill and Charlotte
http://www.healthscout.com/cgi-bin/WebObjects/Af?ap=55&id=108241
'Super Gene' May Hold Brain
Secrets
Scientists hope to unravel fetal brain growth
By Nicolle Charbonneau
HealthScout Reporter
THURSDAY, Feb. 15
(HealthScout) -- When
scientists print out a paper
copy of the chemical
instructions for an average
gene, it's roughly the size of an
open newspaper.
But when geneticists at the
Hospital for Sick Children in
Toronto printed out the codes
for a new gene they'd discovered, the printout stretched
down an entire corridor of the building.
The new gene, called CNTNAP2, is between 50 and
100 times larger than the average gene, but its
tremendous size may be more than just an interesting
piece of trivia. Its discoverers think it may hold the
genetic blueprints that dictate how the brain develops in
a growing fetus.
Not only do these findings advance our basic
knowledge of the brain, they say, but they also raise
hopes of future treatments for neurological disorders
that begin in the womb.
The gene was discovered last summer by Stephen
Scherer and Kazuhiko Nakabayashi as part of a
project to map all genes on the human chromosome 7.
Each cell in the body contains 23 pairs of
chromosomes. Each of the 46 chromosomes is made
up of a coiled strand of DNA, which contains the
genetic information that makes us who we are.
The researchers say they immediately noticed they were
dealing with a larger-than-normal gene. The average
gene contains 20,000 to 50,000 base pairs of
nucleotides, which contain the instructions for that
gene's proteins, but this new gene contains at least 2.3
million base pairs.
"The human genome has diversity," says Nakabayashi.
Thanks to the Human Genome Project, the U.S.
government-coordinated effort to map the genetic
makeup of people, the study was completed in a matter
of months, rather than years, he says. Details appear in
this month's issue of the journal Genomics.
Research by a different laboratory found that the
protein produced by this gene is limited to the brain, but
the Toronto team found that the gene requires more
than 16 hours to produce that protein, Nakabayashi
says.
"That is a long one," says Roger Reeves, a professor of
physiology and affiliate member of the Center for
Genetics at Johns Hopkins University in Baltimore.
"That would be directly a function of its size. It requires
more work to make it."
"In order to make a protein,that means transcribing
the entire gene," Reeves says. "Most genes would be
under 10,000 base pairs, so you can see that the time
required to make a gene that was 200 times bigger than
that is probably going to be longer."
According to the researchers, the long period of time
required to make the protein points to a process that
also occurs over a long period of time -- like a
pregnancy.
The gene would not be the first that's expressed in the
early brain. "There are quite a few that are known to be
involved in brain development from the very earliest
time points in embryogenesis until much later on, up to
specific things that would trigger important processes in
development and maturation of neurons," Reeves says.
And this newly discovered "super gene" already might
have potential implications for those with certain
hereditary disorders.
"This gene is a candidate gene for hearing loss,"
Nakabayashi says. The researchers already suspect
that it may play a role in a type of deafness that occurs
when children are born without hearing in either ear.
Together with French researchers, the Toronto
scientists are launching a study of people with this rare
inherited hearing disorder, hoping to find the mutation
on the gene that leads to this condition.
What To Do
For more information on the Human Genome Project,
visit the Web sites for the Howard Hughes Medical
Institute or Scientific American.
If you get bogged down by the scientific lingo, this
glossary of genetic terms from the National Human
Genome Research Institute should help.
Or, you might want to read previous HealthScout
articles on the gene mapping project.
SOURCES: Interviews with Kazuhiko Nakabayashi, Ph.D.,
postdoctoral
fellow, department of genetics, Hospital for Sick Children,
Toronto; and
Roger H. Reeves, Ph.D., professor, department of physiology, and
affiliate member, Center for Genetics, department of medicine,
Johns
Hopkins University School of Medicine, Baltimore; February 2001
Genomics
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Copyright © 2001 Rx Remedy, Inc.
Last updated 02/15/01
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