UCSF research reveals how the embryo brings its hear...( ve found for bringing the two parts of...)

If it serves this role for the zebrafish heart, Stainier suggests, it probably performs the same function in the human embryo.

"And as we start to understand the molecular pathways involving S1P by studying heart formation in zebrafish, we should learn something about how it regulates other processes such as wound healing," he says.

In 1996, Stainier and colleagues published the identity of 58 different mutations affecting zebrafish heart development. These they had selected from a much larger number of mutations produced by exposing the zebrafish genome to a chemical agent. They zeroed in on the most interesting genes by examining the developmental problems their mutations caused. One mutation that prevented the primordial heart halves to join was named miles apart by a post-doctoral researcher pining for his lover across the sea. In the embryos affected by the miles apart mutation, the researchers found, the two primordial heart tubes failed to converge to the midline.

In the current research reported in Nature, Stainier's lab isolated the miles apart gene and went on to show that the gene codes for a receptor, or docking site, for S1P. They determined that the receptors are concentrated in the midline region toward which the two heart buds migrate. Presumably, when S1P molecules dock with their miles apart receptors, they create a field that attracts or allows the primordial heart buds to migrate to the midline. There they find each other and fuse.

The discovery that S1P is essential for the normal union of the zebrafish heart is surprising, Stainier says, because most molecules that guide developing cells to their destiny -- all discovered in the last five to ten years -- are proteins, the conventional cellular workhorses produced directly from genetic instructions. But S1P is a lipid - an oily substance produced not from a genetic code but as a product o
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Contact: Wallace Ravven
wravven@pubaff.ucsf.edu
415-476-2557
University of California - San Francisco
11-Jul-2000