Department of Molecular & Cell Biology
University of California, Berkeley
“Transcriptional Gene Networks and Dorso-Ventral Polarity in Fly Embryo”
Tuesday, February 13, 2007 @ 4:00 PM
Life Science Complex, RM 038
Abstract: Gradients of transcription factors control spatial gene expression during early Drosophila development. Transcription regulatory regions, enhancers (or cis –Regulatory Modules), mediate gene response to the transcriptional gradients. It is still unclear how structure of the enhancer sequences (i.e. identity, quality, spacing, and orientation of transcription factor binding sites) contributes to the precision of transcriptional response and formation of spatial gene expression.
To explore the contribution of enhancer sequences, a group of Dorsal target genes has been analyzed, involved into specification of mesoderm (type I genes, twi, sna) and neurogenic ectoderm (type II genes, rho, vn, vnd). Quantitative analysis of the spatial gene expression patterns has shown that the gene response models based on occupancy of binding sites in enhancers produce reasonable approximations.
Observed types of interactions between Dorsal target genes (feed-forward loops) may help to explain gene expression patterns along Anterior-Posterior embryo axis and in some other, seemingly unrelated biological systems, such as eyespot patterns in butterfly wings.