Submitted to: Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 4/17/2004
Publication Date: 4/17/2004
Citation: Gahr, S.A., Rexroad III, C.E. 2004. Genomic characterization and expression of the id protein genes in the rainbow trout (oncorhynchus mykiss). Experimental Biology. April 17-21, 2004. Abstract 233.2.
Technical Abstract: Understanding the biochemical mechanisms that regulate growth and development in rainbow trout will facilitate the genetic improvement of this species for aquaculture production efficiency. The Id (Inhibitors of DNA Binding/Differentiation) proteins are a family of dominant negative bHLH (basic Helix-Loop-Helix) transcription factor regulators whose activities result in delayed cell differentiation and prolonged proliferation. A rainbow trout BAC (bacterial artificial chromosome) library was screened to identify clones containing Id genes using probes designed from species-specific cDNA sequences. Six Id genes were sequenced (Id1, Id1-Like, Id2, Id2-Like, Id6-1, and Id6-2) and show genomic structure and predicted protein features common to Id proteins of different species. Microsatellite markers located near the genes were identified through BAC subcloning and used for genetic mapping for future correlation with economically important traits. Similar to mammals, the rainbow trout Id transcripts present significant overlap in their tissue distribution as determined by real-time PCR. However, analyses of the transcription factor binding sites in the promoter regions suggest unique regulation of expression for each gene. In addition to economic interest, a wealth of genetic information has been generated from rainbow trout's usefulness as a model organism for studies on human health and evolutionary genetics. Thus far the identification of homeologous Id gene pairs mirrors that of single copy genes in mammals. The data generated in the current study have improved our understanding of the mechanisms regulating growth and development.