Molecular cloning and characterization of OsCHR4, a rice chromatin-remodeling factor required for early chloroplast development in adaxial mesophyll.
Mi-2 protein, the central component of the NuRD nucleosome remodeling and histone deacetylase complex, plays a role in transcriptional repression in animals. Mi-2-like genes have been reported in Arabidopsis, though their function in monocots remains largely unknown. In the present study, a rice Mi-2-like gene, OsCHR4 (Oryza sativa Chromatin Remodeling 4, LOC_Os07g03450), was cloned from a rice mutant with adaxial albino leaves. The Oschr4 mutant exhibited defective chloroplasts in adaxial mesophyll, but not in abaxial mesophyll. Ultrastructural observations indicated that proplastid growth and/or thylakoid membrane formation in adaxial mesophyll cells was blocked in the Oschr4 mutant. Subcellular localization revealed that OsCHR4::GFP fusion protein was targeted to the nuclei. OsCHR4 was mainly expressed in the root meristem, flower, vascular bundle, and mesophyll cells by promoter::GUS analysis in transgenic rice. The transcripts of some nuclear- and plastid-encoded genes required for early chloroplast development and photosynthesis were decreased in the adaxial albino mesophyll of the Oschr4 mutant. These observations provide evidence that OsCHR4, the rice Mi-2-like protein, plays an important role in early chloroplast development in adaxial mesophyll cells. The results increase our understanding of the molecular mechanism underlying tissue-specific chloroplast development in plants.
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Science, Zhejiang University, Hangzhou 310058, People's Republic of China.
Chunfang
C
Zhao
Jiming
J
Xu
Yue
Y
Chen
Chuanzao
C
Mao
Shelong
S
Zhang
Youhuang
Y
Bai
Dean
D
Jiang
Ping
P
Wu
D000595:Amino Acid Sequence; D002736:Chloroplasts / Q000235:genetics* / Q000648:ultrastructure; D042002:Chromatin Assembly and Disassembly; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D015536:Down-Regulation / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D061125:Genes, Chloroplast / Q000235:genetics; D018519:Meristem / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D058503:Mesophyll Cells / Q000648:ultrastructure; D009154:Mutation; D009928:Organ Specificity; D012275:Oryza / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D010641:Phenotype; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D058526:Plant Vascular Bundle / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment; D020524:Thylakoids / Q000235:genetics / Q000648:ultrastructure
D010940:Plant Proteins; D011993:Recombinant Fusion Proteins