The study of a novel zinc finger gene cluster TZF and a genomic region flanking the histone H 4 replacement gene H 4 r of Drosophila melanogaster

Abstract

Part I : A zinc finger gene Tzf1 was cloned in the earlier work of the lab by screening a ë-DASH2 cDNA expression library with an anti-Rat SC antibody. A ë-DASH2 genomic DNA library and cosmid lawrist 4 genomic DNA library were screened with the cDNA fragment of Tzf1 to determine the genomic organization of Tzf1. Another putative zinc finger gene Tzf2 was found about 700 bp upstream of Tzf1.RACE experiment was carried out for both genes to establish the whole length cDNA. The cDNA sequences of Tzf and Tzf2 were used to search the Flybase (Version Nov, 2000). They correspond to two genes found in the Flybase, CG4413 and CG4936. The CG4413 transcript seems to be a splicing variant of Tzf transcripts. Another two zinc finger genes Tzf3 and Tzf4 were discovered in silico. They are located 300 bp away from Tzf and Tzf2, and a non-tandem cluster was formed by the four genes. All four genes encode proteins with a very similar modular structure, since they all have five C2H2 type zinc fingers at their c-terminal ends. This is the most compact zinc finger protein gene cluster found in Drosophila melanogaster.Part II: 34,056 bp insert of the cosmid 19G11 , containing the Histone H4 replacement gene H4r was completely sequenced by mapping and subcloning. Computer analysis was carried out with this sequence and 9 new putative genes except for the known genes H4r and punt were identified.Part III: P-element mediated excision was carried out trying to obtain Drosophila melanogaster strains with mutated H4r gene.About 5,000 F2 candidate flies were sorted according the phenotypes and screened with PCR. No mutant could be identified.