Mathew, Sam Jacob (2006) Identification and characterization of a genomic region involved in Drosophila gastrulation. PhD thesis, Universität zu Köln.
Gastrulation in Drosophila begins with ventral furrow formation. Although some genes required for ventral furrow formation have been known, it was evident that as yet unidentified genes were involved in this process. Thus, a screen to identify new loci involved in ventral furrow formation was performed previously, implicating the cytogenetic region 24-25 on the left arm of the second chromosome among other regions. In this study, further genetic analysis of this region was carried out to pinpoint and fine map the locus or loci in the 24-25 region that are responsible for the defect in ventral furrow formation. It was found that at least two genetically separable maternal loci and one zygotic locus were involved in the observed defects. Mapping of the different loci were carried out. The maternal loci were narrowed down to short genomic stretches of 15-20 Kb and a candidate gene for the zygotic effect, Traf1 was identified. Traf1 was identified based on the Traf1 expression pattern. Later, it was found that Traf1 is a Twist target and embryos from available hypomorphic alleles of Traf1 exhibited defects in gastrulation. However, conclusive evidence in this regard requires a complete loss of function allele. Overexpression of Traf1 in the mesoderm also caused defective gastrulation, possibly mediated by the ability of Traf1 to activate the JNK signalling cascade. It was found that the gastrulation defects observed upon overexpression of Traf1 was not due to cell fate changes or abnormal cell division. Further investigations are required to identify the precise processes affected upon such overexpression that lead to gastrulation defects.
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