Trigger Gene For Muscle Development Discovered

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Trigger Gene For Muscle Development Discovered

http://www.sciencedaily.com/releases/2008/01/080131121756.htm

University of Oregon scientists say they have identified a gene that

is the key switch that allows embryonic cells to form into muscles in

zebrafish.

Much like students in a kindergarten class lining up to go to lunch,

the trigger gene, which is identified as Smarcd3, must align

correctly with two other genes for muscle formation to begin, a

process known as myogenesis, said principal investigator Monte

Westerfield, a professor of biology and researcher in the UO

Institute of Neuroscience.

The basic research was done using zebrafish embryos, which provide a

model system for analyzing the genetic control of induction and

specification of muscle cells in vertebrates, as well as for many

other important health issues.

" Our muscles develop from a particular set of cells in the embryo, "

Westerfield said. " These muscle precursor cells need to be in the

right place at the right time to develop into muscles. Previously it

was unknown how the timing of this critical developmental switch is

controlled. We discovered the missing factor, Smarcd3, which forms a

protein complex that alters the shape of DNA in particular regions of

the genome, thus turning on genes required for cells to develop into

muscle. "

Smarcd3 proteins are part of a chromatin-remodeling complex made up

of DNA and proteins that make up chromosomes. It is a transcriptional

protein, which means it is important for initiating, in this case,

development.

The UO researchers found that muscle formation begins in an embryo's

mesoderm when Smarcd3 interacts correctly with two other

transcription-factors known as Fgf and Ntl. This specific time-

sensitive alignment, the researchers noted, works to trigger the

earliest gene expression involved in myogenesis.

Previous research had suggested the requirement of several additional

transcription proteins, but the UO team was able to sort through many

of the combinations and narrow the field to these three factors. The

findings could eventually allow researchers to understand how various

combinations of proteins in the chromatin act to regulate the

development of different cell types, tissues and organs.

The findings were published online ahead of the regular publication

by the Journal of Biological Chemistry. Co-authors with Westerfield

of the JBC paper were two former research associates in Westerfield's

lab: Haruki Ochia, who recently left the UO for the Nara Institute of

Science and Technology in Japan, and Stefan Hans, who now is at the

University of Technology in Dresden, Germany.