title: Human microRNA clusters: genomic organization and expression profile in leukemia cell lines.
abstract: MicroRNAs (miRNAs) play an important role in diverse physiological and developmental processes by negatively regulating expression of target genes at the post-transcriptional level. Here, we globally analyzed the genomic organization of all registered 326 human miRNA genes in miRNA registry 7.1 and found that 148 human miRNA genes appeared in a total of 51 clusters. Alignment of the miRNA sequences in different clusters revealed a significant number of miRNA paralogs among the clusters, implying an evolution process targeting the potentially conserved roles of these molecules. Then we performed Northern blot analysis for expression profiling of all clustered miRNAs in several human leukemia cell lines. Consistent expression of the miRNAs in a single cluster was revealed in 39 clusters, while inconsistent expression of members in a single cluster was detected in the other 12 clusters. Meanwhile, we identified several hematopoietic lineage-specific or -enriched miRNA clusters (e.g., the mir-29c, mir-302, mir-98, mir-29a, and let-7a-1 clusters) and individual miRNAs (e.g., mir-181c, mir-181d, mir-191, and mir-136). These findings may suggest vital roles of these miRNA clusters or miRNAs in human hematopoiesis and oncogenesis, and provide clues for understanding the function and mechanism of miRNAs in various biological processes.
authors.affiliation: National Laboratory of Medical Molecule Biology, Institute of Basic Medical Sciences, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100005, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Yu
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Gui-Hua
authors.initials: GH
authors.lastname: Yang
authors.forename: Fan-Long
authors.initials: FL
authors.lastname: Wang
authors.forename: Yan-Ni
authors.initials: YN
authors.lastname: Ma
authors.forename: Zhan-Wen
authors.initials: ZW
authors.lastname: Du
authors.forename: Jun-Wu
authors.initials: JW
authors.lastname: Zhang
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D019070:Cell Lineage; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D016678:Genome; D006412:Hematopoietic Stem Cells; D006801:Humans; D007938:Leukemia / Q000235:genetics*; D035683:MicroRNAs; D008969:Molecular Sequence Data; D005810:Multigene Family; D009693:Nucleic Acid Hybridization
chemical_list: D035683:MicroRNAs