Identification of chromatin remodeler FUN30 facilitating transcription elongation through nucleosome disassembly

Abstract

Although nucleosome is known to disturb the elongation of RNA polymerase II (RNAPII), the detailed mechanism to facilitate nucleosome disassembly during RNAPII elongation is not well understood in vivo. This study identifies $Fun30^{Fft3}$ as the chromatin remodeler which promotes RNAPII elongation by facilitating nucleosome disassembly in fission yeast. $Fun30^{Fft3}$ is required to maintain RNAPII occupancy in transcription elongation-related histone chaperone FACT-dependent manner. And $Fun30^{Fft3}$ is recruited at transcribed regions in transcription-dependent manner and associates with RNAPII and RNAPII elongation-related factors. Surprisingly, simple mathematical approach suggests that $Fun30^{Fft3}$ facilitates transcription-coupled nucleosome disassembly which is correlated with RNAPII regulation function of $Fun30^{Fft3}$. Furthermore, nucleosome-barrier relieving mutations defective to histone deacetylase complex Clr6 complex II and histone level suppress the both growth and RNAPII occupancy defects of cells lacking $Fun30^{Fft3}$. These results suggest that RNAPII uses the chromatin remodeler $Fun30^{Fft3}$ to facilitate nucleosome disassembly during transcription elongation in vivo.