title: A NAP-Family Histone Chaperone Functions in Abiotic Stress Response and Adaptation.
abstract: Modulation of gene expression is one of the most significant molecular mechanisms of abiotic stress response in plants. Via altering DNA accessibility, histone chaperones affect the transcriptional competence of genomic loci. However, in contrast to other factors affecting chromatin dynamics, the role of plant histone chaperones in abiotic stress response and adaptation remains elusive. Here, we studied the physiological function of a stress-responsive putative rice (Oryza sativa) histone chaperone of the NAP superfamily: OsNAPL6. We show that OsNAPL6 is a nuclear-localized H3/H4 histone chaperone capable of assembling a nucleosome-like structure. Utilizing overexpression and knockdown approaches, we found a positive correlation between OsNAPL6 expression levels and adaptation to multiple abiotic stresses. Results of comparative transcriptome profiling and promoter-recruitment studies indicate that OsNAPL6 functions during stress response via modulation of expression of various genes involved in diverse functions. For instance, we show that OsNAPL6 is recruited to OsRad51 promoter, activating its expression and leading to more efficient DNA repair and abrogation of programmed cell death under salinity and genotoxic stress conditions. These results suggest that the histone chaperone OsNAPL6 may serve a regulatory role in abiotic stress physiology possibly via modulating nucleosome dynamics at various stress-associated genomic loci. Taken together, our findings establish a hitherto unknown link between histone chaperones and abiotic stress response in plants.
authors.affiliation: Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India (A.K.T., S.L.S.-P.); andStress Physiology and Molecular Biology, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India (A.P.).
authors.forename: Amit K
authors.identifier: 0000-0002-4624-7282
authors.initials: AK
authors.lastname: Tripathi
authors.affiliation: Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India (A.K.T., S.L.S.-P.); andStress Physiology and Molecular Biology, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India (A.P.).
authors.forename: Ashwani
authors.initials: A
authors.lastname: Pareek
authors.affiliation: Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India (A.K.T., S.L.S.-P.); andStress Physiology and Molecular Biology, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India (A.P.) sneh@icgeb.res.in.
authors.forename: Sneh Lata
authors.initials: SL
authors.lastname: Singla-Pareek
mesh_terms: D000222:Adaptation, Physiological; D017209:Apoptosis; D004249:DNA Damage; D004260:DNA Repair; D055864:Droughts; D020869:Gene Expression Profiling; D055785:Gene Knockdown Techniques; D056488:Histone Chaperones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020287:In Situ Nick-End Labeling; D019913:Nuclear Localization Signals / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism; D012275:Oryza / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D054712:Salinity; D013312:Stress, Physiological
chemical_list: D056488:Histone Chaperones; D019913:Nuclear Localization Signals; D009707:Nucleosomes; D010940:Plant Proteins