Education Trust
Publishes on Developmental Biology and Gene Regulation, Meteorological Phenomena and Simulations, Retinal Development and Disorders. 393 papers and 19.1k citations.
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We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.
In recent years, skeletal muscle has become an important model for understanding the mechanisms that regulate tissue-specific gene expression. The formation of skeletal muscle during embryogenesis involves commitment of mesodermal progenitors to the myogenic lineage and subsequent differentiation of skeletal myoblasts into terminally differentiated myotubes. Like many cell types, skeletal myoblasts do not express markers of terminal differentiation until they are forced to exit the cell cycle in response to environmental cues. Growth factor signals play a central role in regulating the program for muscle-specific transcription by maintaining myoblasts in a proliferative state that is nonpermissive for the expression of muscle-specific genes.
math5 is a murine orthologue of atonal, a bHLH proneural gene essential for the formation of photoreceptors and chordotonal organs in Drosophila. The expression of math5 coincides with the onset of retinal ganglion cell (RGC) differentiation. Targeted deletion of math5 blocks the initial differentiation of 80% of RGCs and results in an increase in differentiated amacrine cells. Furthermore, the absence of math5 abolishes the retinal expression of brn-3b and the formation of virtually all brn-3b-expressing RGCs. These results imply that math5 is a proneural gene essential for RGC differentiation and that math5 acts upstream to activate brn-3b-dependent differentiation processes in RGCs.