Poster abstracts
Poster number 70 submitted by Jan Kucinski
RNase H1 is required for Arabidopsis thaliana embryonic development
Jan Kucinski (University of Michigan, Department of Molecular, Cellular and Developmental Biology, Ann Arbor, MI, USA), Sebastian Chamera, Aleksandra Kmera (Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland), M. Jordan Rowley (Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE), Pragya Khurana (University of Michigan, Department of Molecular, Cellular and Developmental Biology, Ann Arbor, MI, USA), Marcin Nowotny (Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland), Andrzej T. Wierzbicki (University of Michigan, Department of Molecular, Cellular and Developmental Biology, Ann Arbor, MI, USA)
Abstract:
RNase H1 is an endonuclease specific towards the RNA strand of RNA:DNA hybrids. Members of this protein family are present in most living organisms and are essential for removing RNA that base pairs with DNA. It prevents detrimental effects of RNA:DNA hybrids and is involved in several biological processes. We show that Arabidopsis thaliana contains at least three RNase H1-like proteins originating from two gene duplication events and alternative splicing. These proteins have the canonical RNase H1 activity, which requires at least four ribonucleotides for enzymatic activity. One of those proteins is nuclear, one is localized to plastids, one is localized to mitochondria. While the nuclear RNase H1 is dispensable for development under normal growth conditions, the presence of at least one organellar RNase H1 is required for embryonic development. The plastid protein RNH1C affects plastid DNA copy number and sensitivity to replicative stress. This suggests that three genomes present in each plant cell are served by at least one specialized RNase H1 protein.
Keywords: RNase H1, Arabidopsis, RNADNA hybrid