Analysis of alternative splicing regulation in the hypervariable receptor Dscam

Hemani, Yash Ramesh (2013). Analysis of alternative splicing regulation in the hypervariable receptor Dscam. University of Birmingham. Ph.D.

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Abstract

The pattern recognition receptor Dscam is a key molecule mediating innate immunity and wiring of the nervous system in Drosophila. Intriguingly, massive molecular diversity is generated by alternative splicing in three exon clusters of Dscam. Upon pathogen exposure in Anopheles gambiae, the AgDscam splicing pattern changes to express isoforms that bind pathogens with higher affinity. In order to test the generality of Dscam splicing regulation in Drosophila, similar experiments involving microbial exposure were carried out, which also showed changes in Dscam splicing pattern. Mutants in RNA regulatory pathways and in the RNA binding protein ELAV were analyzed due to their similar mutant phenotypes in nervous system development as Dscam. In each of these mutants, alterations of Dscam alternative splicing in a cluster specific manner were observed, eluding a unique mechanism for any of the analyzed pathways. In ELAV mutants, one of the three clusters of alternatively spliced exons is dramatically mis-regulated. Since no ELAV binding site is present in this cluster, genes downstream of ELAV could mediate mis-regulation of alternative splicing. From the analysis of mutants in ELAV differentially regulated genes it was concluded that Dscam alternative splicing is most prominently affected by chromatin remodeling factors, along with RNA binding proteins, DNA binding proteins and small-RNA processing factors. A heterologous transgene for expression of Dscam pre-mRNA in Drosophila was also developed to characterize the role of the chromatin state in alternative splicing.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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