Maurya, Ashish K2013-11-072013-11-0720062006Source: Masters Abstracts International, Volume: 45-05, page: 2356.http://hdl.handle.net/10393/27391http://dx.doi.org/10.20381/ruor-18683Vertebrate Dlx genes code for homeodomain (a conserved DNA binding domain) transcription factors involved in the development of the forebrain, craniofacial skeleton, dentition, sensory organs and limbs. Vertebrates have at least 6 Dlx genes whereas invertebrates have only one Dlx homologue (called the distal-less or Dll gene) (Stock, Ellies et al. 1996). Vertebrate Dlx genes are organized as pairs of convergently transcribed genes. The intergenic region between each of these bigenes contains at least two highly conserved sequences (300-500bp each) that act as enhancers of transcription of the flanking Dlx genes. Activity of these enhancers when tested with reporter genes (GFP and LacZ) in transgenic zebrafish and mice recapitulates the endogenous Dlx expression patterns. Here we are investigating Dlx regulation in lamprey, an agnathan species and a sister group of gnathostomes. In doing this we hope to (1) trace back the origin of the conserved Dlx intergenic enhancers found in vertebrates and (2) address the question, can the differences in regulation of lamprey Dlx genes with that of gnathostomes account for some of the morphological differences seen in lampreys (like absence of jaws)? We have shown that lamprey have at least four Dlx genes (A, B, C, D), two of which are arranged in the bigenic configuration seen in other vertebrates. We were unable to find the presence of the conserved intergenic enhancers by Southern hybridization and PCR experiments within this lamprey Dlx intergenic region. We have shown that this region can target expression of reporter genes in the forebrain, branchial arches and trunk somites when tested in zebrafish embryos in a reporter gene assay, suggesting many of the Dlx regulatory mechanisms are conserved between lamprey and gnathostomes.137 p.enBiology, Molecular.Biology, Genetics.Thesis