Structures and dynamics of Rpd3S complex bound to nucleosome

Area of Science:

• Molecular Biology
• Structural Biology
• Epigenetics

Background:

• The Rpd3S complex is essential for regulating transcription by deacetylating histones in transcribed regions.
• It plays a key role in suppressing unwanted transcription initiation within genes.

Purpose of the Study:

• To determine the high-resolution structures of the Rpd3S complex.
• To elucidate the structural basis for Rpd3S-nucleosome interactions.
• To reveal the mechanism by which Rpd3S engages different deacetylation sites.

Main Methods:

• Cryo-electron microscopy (cryo-EM) was employed to obtain atomic-resolution structures.
• The study analyzed the Rpd3S complex in its apo state and bound to mononucleosomes.

Main Results:

• The structures reveal the architecture of Rpd3S, showing its ability to bind a mononucleosome without linker DNA.
• The Rpd3S core utilizes positive-charged anchors to connect with nucleosomal DNA.
• Three distinct orientations of the Rpd3S core relative to the nucleosome were observed, positioning the Rpd3 deacetylase differently.

Conclusions:

• The study provides a structural framework for understanding Rpd3S function.
• A dynamic working model for Rpd3S engaging diverse deacetylation sites is proposed.
• These findings offer insights into the epigenetic regulation of transcription.