title: Genomewide analysis of intronic microRNAs in rice and Arabidopsis.
abstract: MicroRNAs (miRNAs) are potent regulators of gene transcription and posttranscriptional processes. The majority of miRNAs are localized within intronic regions of protein-coding genes (host genes) and have diverse functions in regulating important cellular processes in animals. To date, few plant intronic miRNAs have been studied functionally. Here we report a comprehensive computational analysis to characterize intronic miRNAs in rice and Arabidopsis. RT-PCR analysis confirmed that the identified intronic miRNAs were derived from the real introns of host genes. Interestingly, 13 intronic miRNAs in rice and two in Arabidopsis were located within seven clusters, of which four  polycistronic clusters contain miRNAs derived from different families, suggesting that these clustered intronic miRNAs might be involved in extremely complex regulation in rice. Length analysis of miRNA-carrying introns, promoter prediction and qRT-PCR analysis results indicated that intronic miRNAs are coexpressed with their host genes. Expression pattern analysis demonstrated that host genes had a very broad expression spectrum in different stages of development, suggesting the intronic miRNAs might play an important role in plant development. This comparative genomics analysis of intronic miRNAs in rice and Arabidopsis provides new insight into the functions and regulatory mechanisms of intronic miRNAs in monocots and dicots.
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
authors.forename: G D
authors.initials: GD
authors.lastname: Yang
authors.forename: K
authors.initials: K
authors.lastname: Yan
authors.forename: B J
authors.initials: BJ
authors.lastname: Wu
authors.forename: Y H
authors.initials: YH
authors.lastname: Wang
authors.forename: Y X
authors.initials: YX
authors.lastname: Gao
authors.forename: C C
authors.initials: CC
authors.lastname: Zheng
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant / Q000235:genetics*; D007438:Introns / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity
chemical_list: D035683:MicroRNAs; D018749:RNA, Plant