Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.641053
Title: Characterisation of nuclear cap-binding complex in Drosophila melanogaster
Author: Arif, Lubna
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2001
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Abstract:
This thesis aims to characterise CBC in Drosophila melanogaster and uses genetic approaches to further understand the mechanisms by which the cap facilitates multiple aspects of RNA metabolism through CBC. Firstly, P-element induced mutagenesis was used to create mutants in the CBC heterodimer. A P-element residing in DmCBP20 was mobilised to generate DmCBP20 excision alleles. This showed DmCBP20 is an essential gene that functions in both somatogenesis and gametogenesis. Intriguingly, the P-hop generated a surprisingly high number of DmCBP20 male steriles lines compared to DmCBP20 female sterile lines. Analysis of male steriles showed the early stages of spermatogenesis that correlate to active transcription and RNA processing are normal. Instead, defects appear to arise in late spermatid differentiation. These findings suggest novel function(s) for DmCBP20 in spermatogenesis outwith RNA processing. A second divergent CBP80 homologue named DmCBP80 Related (DmCBP80R) is identified in fruitflies. In contrast to DmCBP80, DmCBP80R appears to be predominantly expressed in adult testes. These results suggest DmCBP80R, together with DmCBP20, might have acquired novel functions in spermatogenesis as part of a male-specific CBC. Finally, to identify CBC-interacting genes, the GAL4-UAS system was used to over-express full-length and truncated CBP20 and CBP80 in non-essential adult fly tissues. The shortest truncations in both cap-binding proteins generated dominant phenotypes. DmCBP80 dominant phenotype was used in genetic modifier screens to identify CBC-interacting genes. This showed the dominant phenotype was suppressed by an allele of the largest subunit of RNAP II that has a truncated CTD. These results suggest CBC might interact with the CTD of RNAP II to facilitate the coupling of transcription with pre-mRNA splicing and RNA 3’-end formation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.641053  DOI: Not available
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