FUNCTIONAL ANALYSIS OF A NEW bHLH FAMILY, hesr-1, -2, -3: POTENTIAL REGULATORS OF VERTEBRATE

In vertebrate embryonic development, segmentation arises through a process that subdivides the paraxial mesoderm of the segmental plate into repeating metameric units called somites. How do cells of the segmental plate recognize their position and form discrete somite units? Recent studies indicate that this process involves in Notch signaling pathway, including the Notch-1, Delta-1 and Delta-3, RBPJ-Kappa, Presenilin-1 and Lunatic fringe. Identification and characterization of a group of the hairy and E(spl) related genes in Drosophila suggest that these proteins act as nuclear effectors for the Notch signaling pathway. Recently, an avian hairy like gene, c-hairy1 has been identified and shown to be expressed in the presomitic mesoderm in a cyclic fashion with temporal periodicity corresponding to the formation time of one somite. Here we report the cloning and expression analysis of a novel mouse hairy and E(spl) related subfamily, called hairy and E(spl) related gene (hesr) -1, -2, and -3