Accepted_test

Two-domain HMGB proteins HMGB1 and HMO1 have different effects on the structure of nucleosomes and chromatosomes

by Malinina Daria | Sivkina Anastasia | Khodyreva Svetlana | Lavrik Olga | Studitsky Vasily | Feofanov Alexei | Biology Faculty, Lomonosov Moscow State University, Moscow, Russia | Biology Faculty, Lomonosov Moscow State University, Moscow, Russia | Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russia | Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russia | Biology Faculty, Lomonosov Moscow State University, Moscow, Russia; Fox Chase Cancer Center, Philadelphia, USA | Biology Faculty, Lomonosov Moscow State University, Moscow, Russia; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia

Abstract ID: 460

Event: BGRS-abstracts

Sections: [Sym 11] Section “Transcription, splicing, translation”

HMO1 and HMGB1 are two members of high mobility group B (HMGB) protein family, which participate in transcription and replication. Despite their homology and structural similarity, they have been proposed to play different roles in the organization of chromatin: while HMGB1 destabilizes nucleosomes, HMO1 stabilizes chromatin by acting as an alternative linker histone. In this study we used EMSA and single particle Förster resonance energy transfer (spFRET) microscopy to characterize how HMO1 and HMGB1 affect nucleosome and chromatosome. It is found that HMO1 significantly affects the conformation of nucleosomal DNA and causes a separation of linker DNA even in chromatosome, but does not evict H1.0 from complex with nucleosome. In contrast, HMGB1 binding has no effect on nucleosomal DNA conformation, but results in a decrease in the distance between the linker DNA helices, and destabilizes chromatosomes by releasing linker DNA from the complex with H1.0 histone.