Genetic on-off switches pinpointed in human genome

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Genetic on-off switches pinpointed in human genome

30 Jun 2005 Medical News Today

In another step to decipher information in the human genome,

scientists have discovered the location and sequence of over 10,000

DNA regions that function as genetic on-off switches, or " promoters "

in human fibroblasts. Fibroblasts are relatively generic, easily

maintained, human cells that form connective tissues throughout the

body. By knowing the specific sequences of DNA that control the

nearly 8,000 active genes in fibroblasts, scientists can tease apart

the biochemical regulation system these cells use to turn genes on

and off during normal growth.

The so-called " promoter map " will not only provide new insight into

how genes are controlled in fibroblasts, but will also serve as a

framework for analysis of genetic control in other human cell types,

tissues and perhaps organs.

The project, detailed in a June 29 electronic edition of the journal,

Nature, is a collaboration headed by Bing Ren at University of

California, San Diego, working with scientists at University of

California, Los Angeles (UCLA) and the company Nimblegen, Inc., in

Madison, Wisc.

Understanding the on-off control mechanisms will further

understanding of how a cell is programmed to perform specialized

functions. Nearly all cells in the human body have the same genetic

information. But they don't all express it at the same time. Cells in

the heart, for example, express different information than do cells

of the liver or brain. Controlled gene activity at certain times

determines what function the cell will have in the body.

To accomplish the genome-wide promoter survey, Bing Ren and his co-

worker, Tae Hoon Kim, conceived and designed a novel experimental

procedure based on cutting-edge microarray technology. UCLA's

Yingnian Wu and Ming Zheng developed sophisticated computer

algorithms to process the massive amount of data collected from the

experiments.

The researchers report that multiple promoters often control a single

gene in parallel, adding another layer to an already complex genetic

regulation mechanism. They also discovered promoters in front of DNA

sequences not previously recognized as genes. The significance of

that finding will be determined in future studies.

Wu and co-investigator, Song Chun Zhu, are supported by the National

Science Foundation's Computer and Information Science and Engineering

directorate.

The National Science Foundation (NSF) is an independent federal

agency that supports fundamental research and education across all

fields of science and engineering, with an annual budget of nearly

$5.47 billion. NSF funds reach all 50 states through grants to nearly

2,000 universities and institutions. Each year, NSF receives about

40,000 competitive requests for funding, and makes about 11,000 new

funding awards. The NSF also awards over $200 million in professional

and service contracts yearly.

National Science Foundation

http://www.nsf.gov