Title

The role of retroviruses and RNA in mammalian centromere competency

Date of Completion

January 2008

Keywords

Biology, Molecular|Biology, Genetics

Degree

Ph.D.

Abstract

The transcriptional framework of the eukaryotic centromere core has been described in budding yeast and rice, but for most eukaryotes and all vertebrates it remains unknown. The lack of large pericentric repeats in the tammar wallaby has made it possible to map the genomic features at the centromere core in a mammalian species for the first time. The centromere of the tammar wallaby is comprised of interspersed arrays of satellite and retroviral DNA. This thesis reports on the finding of a novel size class of small RNA produced from satellite and retroviral transcriptional units at the centromere. Deep sequencing reveals these small RNAs are enriched for retroelements and retroelement-contiguous sequences at the centromere. Results implicate a role for retroviral promoters in transcription of this new class of small RNA and indicate a role in centromere function and regulation of cell division. The discovery of this new RNA form, transcribed from mammalian centromeres, brings together several independent lines of evidence that point to a conserved, retroviral-encoded RNA entity at the core of mammalian centromeres. ^