Only a few targets of the sex determining genes are known - <i>dsf, fru, </i>and the <i>yps. </i> Such genes would be expected to fit into one of three categories: (i) Genes expressed exclusively in one sex; (ii) Genes expressed at a higher level in one sex than the other; (iii) Genes that are expressed at similar levels in both sexes, but produce sex-specific transcripts. In an attempt to isolate genes that fit into these categories a non-gonadal differential screen of an adult body genomic DNA library was performed, using sex-specific radio-labelled cDNA. The genomic recombinant fs(1) was chosen for further analysis based on its preferential hybridisation to female non-gonadal cDNA. Screening of cDNA libraries using fs(1) sequence isolated two cDNAs, a 3.0kb cDNA (cDNA<sup>A</sup>) and a 4.5kb cDNA (cDNA<sup>B</sup>). Sequence analysis revealed that both these cDNAs encoded a novel opa repeat-containing serine/threonine protein kinase, the difference in the cDNAs being the length of the 5' and 3' untranslated regions (UTRs). The gene, which maps to polytene position 61A, was named <i>Drosophila serine/threonine protein kinase@61 (Dstpk61). </i>Northern analysis showed there to be at least 4 different <i>Dstpk61 </i>transcripts: a 3.0kb testis-specific transcript (possibly represented by cDNA<sup>A</sup>); a 3.5kb ovary-specific transcript; a 4.5kb female-specific carcass transcript (possibly represented by cDNA<sup>B</sup>); and a slightly larger non-sex-specific transcript. The work presented here shows that <i>Dstpk61</i> is a complex gene that produces multiple transcripts by using alternative promoters, alternative polyadenylation sites, and alternative splicing. It is now known to have significant sequence and functional homology to mammalian Phosphoinositol-dependent kinase 1 (PDK1), which has been implicated in the insulin signal transduction pathway and the regulation of apoptosis. Four mutant P-insertion lines have been identified that disrupt <i>Dstpk61</i> at different sites. The phenotypes of these mutants, possible <i>Dstpk61</i> transcripts, and the observed mRNA expression pattern are discussed in relation to the possible role of Dstpk61 protein in <i>Drosophila</i> development.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:643283 |
| Date | January 1999 |
| Creators | Clyde, Dorothy |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11993 |
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