Does a GATA factor make the bed for centromeric nucleosomes?

Abstract

CENP-A is an evolutionarily conserved, centromere-specific histone H3 variant. It remains a great mystery how CENP-A is correctly incorporated into the centromere, a restricted chromosomal region, despite the presence of an overwhelming amount of histone H3. We identified a cell cycle-regulated GATA factor, Ams2, as a component of the CENP-A localization pathway in fission yeast. Unexpectedly, this putative transcription factor, which belongs to a protein family containing members that remodel nucleosomes, appeared to bind to and function at the central region of the centromere. Although the centromere has in general been considered transcriptionally inactive, fission yeast's outer centromeric region has recently been shown to encode non-translated snRNAs that are involved in heterochromatin formation. Transcription factors such as Ams2 may directly transcribe some unidentified non-translated centromeric RNAs. Transcription and/or remodeling of the nucleosomes at the centromeres may be important for the precise incorporation of CENP-A in fission yeast.