title: Characterization and expression profiles of miRNAs in rice seeds.
abstract: Small RNAs (sRNAs) are common and effective modulators of gene expression in eukaryotic organisms. To characterize the sRNAs expressed during rice seed development, massively parallel signature sequencing (MPSS) was performed, resulting in the obtainment of 797,399 22-nt sequence signatures, of which 111,161 are distinct ones. Analysis on the distributions of sRNAs on chromosomes showed that most sRNAs originate from interspersed repeats that mainly consist of transposable elements, suggesting the major function of sRNAs in rice seeds is transposon silencing. Through integrative analysis, 26 novel miRNAs and 12 miRNA candidates were identified. Further analysis on the expression profiles of the known and novel miRNAs through hybridizing the generated chips revealed that most miRNAs were expressed preferentially in one or two rice tissues. Detailed comparison of the expression patterns of miRNAs and corresponding target genes revealed the negative correlation between them, while few of them are positively correlated. In addition, differential accumulations of miRNAs and corresponding miRNA*s suggest the functions of miRNA*s other than being passenger strands of mature miRNAs, and in regulating the miRNA functions.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300, Fenglin Road, 200032 Shanghai, China.
authors.forename: Liang-Jiao
authors.initials: LJ
authors.lastname: Xue
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Zhang
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Xue
mesh_terms: D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D035683:MicroRNAs / Q000737:chemistry / Q000378:metabolism*; D012275:Oryza / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D022661:RNA, Untranslated / Q000145:classification; D018626:Retroelements; D012639:Seeds / Q000235:genetics* / Q000378:metabolism
chemical_list: D035683:MicroRNAs; D022661:RNA, Untranslated; D018626:Retroelements