Investigating the role of centromeric RNA transcripts for centromere function and inheritance

The centromere is a unique chromatin domain important for proper segregation of chromosomes during mitosis. In most organisms, the position of the centromere is determined epigenetically by the centromere-specific incorporation of the H3-variant CENP-A Transcription at centromeres has been linked to the deposition of new CENP-A, although it is unclear whether transcription or the produced RNA are equally important. We and others have recently found that several components of the transcriptional machinery including RNA Polymerase II (RNAPII) and centromere-associated RNA transcripts temporally coincides with CENP-A loading in mitosis to G1. While we have evidence cells that the transcriptional process itself is required for CENP-A deposition at the centromere, this does not rule out a role for the centromeric transcripts themselves. To investigate this further we will purify nascent centromeric RNA transcripts, match them to the underlying centromeric DNA and identify potential binding partners. We will then aim to dissect the roles of transcription and RNA transcripts by specifically targeting transcriptional repressors or RNases to centromeric loci and investigate centromere inheritance and function. This work will be performed using Drosophila tissue culture cells as an ideal model system for simple centromeres.

http://www.wcb.ed.ac.uk/research/patrick-heun