Packaging to Control Gene Expression

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See : http://www.newscientist.com/news/news.jsp?id=ns99991140

Breakthrough research on proteins once thought to be simply " packaging "

for DNA may have revealed a master on/off gene switch, say US

researchers.

If the switch is as important as the scientists believe, its discovery

should lead to new treatments for disease and provide vital information

for researchers who hope to one day grow whole replacement organs from

embryonic stem cells, says Allis of the University of Virginia.

Allis co-authored one of a series of new journal papers revealing

details of the " histone methylation switch " . Histones are proteins that

DNA coils around to form " chromatin " in a cell nucleus.

....

Previous research has indicated that the addition of acetyl groups to

histones helps regulate individual gene expression. The adding of a

methyl group to DNA is also involved in the switching on and off of

single genes. But what seems to make the methylation of histone

different is its ability to stably set large stretches of our genome to

on or off, says Allis.

The research was conducted by researchers at the University of

Virginia, Cold Spring Harbour Laboratory, NIH and the Vienna Biocentre

in Austria. Each of the teams focused on the same histone protein - and

found that the presence or absence of a methyl group seemed to be the

key to whether associated genes were active or repressed.

--

LEF has made much of the influence of methylation in the turning on of

age-related genes and the turning off of anti-oncogenes. They didn't

attack the issue of genes which turn on or off in groups. The above

research will fill that gap.

This is the kind of research that can't be done with adult stem cells

and which may even be questionable with stem cell lines. The only way to

be sure that age-related switching has not already taken place is to

utilize cells that haven't experienced more than a few doublings.

Bob Cruder - Denver, Colorado, USA

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Flavius phus writes: Seizing her child, an infant at the breast, she

cried, " My poor baby, why should I keep you alive in this world of war

and famine? Even if we live till the Romans come, they will make slaves

of us; and anyway, hunger will get us before slavery does; and the

rebels are crueler than both. Come, be food for me, and an avenging fury

to the rebels, and a tale of cold horror to the world to complete the

monstrous agony of the Jews. " With these words she killed her son,

roasted the body, swallowed half of it, and stored the rest in a safe

place. http://www.rjgeib.com/thoughts/desolation/josephus.html