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miRNA Genes (mirna + gene)
Selected AbstractsFunctional analysis of lung tumor suppressor activity at 3p21.3GENES, CHROMOSOMES AND CANCER, Issue 12 2006Arja ter Elst The early and frequent occurrence of deletions at 3p21.3 in lung cancer has led to the consideration of this chromosomal region as a lung cancer (LUCA) critical region with tumor suppressor activity. We covered this 19 genes-containing region with overlapping P1 artificial chromosomes (PACs), in which genes are likely accompanied by their own promoters or other regulatory sequences. With these PACs we transfected cells from a small cell lung cancer (SCLC) cell line which readily caused tumors in nude mice. Per PAC we selected two cell clones with a low number of PAC copies integrated at a single genomic site. The selected clones were s.c. injected into nude mice to investigate whether the integrated genes suppressed the tumor-inducing capacity of the original SCLC cell line. We could demonstrate PAC-specific gene expression in the transfected cells. All of the PAC integration sites were different. It appeared that introduction of a PAC or even an empty PAC vector causes some chromosomal instability, which in principle may either promote or inhibit cell growth. However, both cell clones with integration of the same PAC from the centromeric part of the LUCA region in different genomic sites were the sole pair of clones that caused smaller tumors than did the original SCLC cell line. This suggests that rather than the induced chromosomal instability, the DNA sequence of that PAC, which in addition to two protein-encoding genes contains at least one potential miRNA gene, is responsible for the tumor suppressor activity. © 2006 Wiley-Liss, Inc. [source] MicroRNA expression during chick embryo developmentDEVELOPMENTAL DYNAMICS, Issue 11 2006Diana K. Darnell Abstract MicroRNAs (miRNAs) are small, abundant, noncoding RNAs that modulate protein abundance by interfering with target mRNA translation or stability. miRNAs are detected in organisms from all domains and may regulate 30% of transcripts in vertebrates. Understanding miRNA function requires a detailed determination of expression, yet this has not been reported in an amniote species. High-throughput whole mount in situ hybridization was performed on chicken embryos to map expression of 135 miRNA genes including five miRNAs that had not been previously reported in chicken. Eighty-four miRNAs were detected before day 5 of embryogenesis, and 75 miRNAs showed differential expression. Whereas few miRNAs were expressed during formation of the primary germ layers, the number of miRNAs detected increased rapidly during organogenesis. Patterns highlighted cell-type, organ or structure-specific expression, localization within germ layers and their derivatives, and expression in multiple cell and tissue types and within sub-regions of structures and tissues. A novel group of miRNAs was highly expressed in most tissues but much reduced in one or a few organs, including the heart. This study presents the first comprehensive overview of miRNA expression in an amniote organism and provides an important foundation for investigations of miRNA gene regulation and function. Developmental Dynamics 235:3156,3165, 2006. © 2006 Wiley-Liss, Inc. [source] Correlated expression patterns of microRNA genes with age-dependent behavioural changes in honeybeeINSECT MOLECULAR BIOLOGY, Issue 4 2010S. K. Behura Abstract The hive-living honeybees (Apis mellifera) show age-dependent behavioural changes; young bees usually nurse the broods in the colony and the older bees engage in foraging activities. These developmentally regulated behavioural changes were previously shown to be correlated with genome-wide transcriptional changes in the honeybee brain. The indigenous small regulatory RNA molecules, known as microRNAs (miRNAs), are potent regulators of gene expression and also are developmentally regulated. Thus, we wanted to study if there might be correlation of differential expression of miRNA genes in the brain with age-dependent behavioural changes of the bees. We determined expression patterns of a set (n= 20) of predicted miRNA genes, by quantitative real-time PCR assays, in the brains of young and old bees that were engaged in nursing or foraging activities in the colony, respectively. Our data show correlated up-regulation of miRNA-124, miRNA-14, miRNA-276, miRNA-13b, let-7 and miRNA-13a in the young nurse bees. miRNA-12, miRNA-9, miRNA-219, miRNA-210, miRNA-263, miRNA-92 and miRNA-283 showed correlated expression patterns in the old forager bees. The modular changes of miRNA genes in the young nurse and old forager bees suggest possible roles of miRNAs in age-dependent behavioural changes in bees. The correlated expression of intronic miRNA genes and their host genes as well as of miRNA genes physically clustered in the genome are also observed. [source] MicroRNA identity and abundance in porcine skeletal muscles determined by deep sequencingANIMAL GENETICS, Issue 2 2010M. Nielsen Summary MicroRNAs (miRNA) are short single-stranded RNA molecules that regulate gene expression post-transcriptionally by binding to complementary sequences in the 3, untranslated region (3, UTR) of target mRNAs. MiRNAs participate in the regulation of myogenesis, and identification of the complete set of miRNAs expressed in muscles is likely to significantly increase our understanding of muscle growth and development. To determine the identity and abundance of miRNA in porcine skeletal muscle, we applied a deep sequencing approach. This allowed us to identify the sequences and relative expression levels of 212 annotated miRNA genes, thereby providing a thorough account of the miRNA transcriptome in porcine muscle tissue. The expression levels displayed a very large range, as reflected by the number of sequence reads, which varied from single counts for rare miRNAs to several million reads for the most abundant miRNAs. Moreover, we identified numerous examples of mature miRNAs that were derived from opposite sides of the same predicted precursor stem-loop structures, and also observed length and sequence heterogeneity at the 5, and 3, ends. Furthermore, KEGG pathway analysis suggested that highly expressed miRNAs are involved in skeletal muscle development and regeneration, signal transduction, cell-cell and cell-extracellular matrix communication and neural development and function. [source] Annotation of 390 bovine miRNA genes by sequence similarity with other speciesANIMAL GENETICS, Issue 1 2009F. Strozzi No abstract is available for this article. [source] Developmental microRNA expression profiling of murine embryonic orofacial tissueBIRTH DEFECTS RESEARCH, Issue 7 2010Partha Mukhopadhyay Abstract BACKGROUND: Orofacial development is a multifaceted process involving precise, spatio-temporal expression of a panoply of genes. MicroRNAs (miRNAs), the largest family of noncoding RNAs involved in gene silencing, represent critical regulators of cell and tissue differentiation. MicroRNA gene expression profiling is an effective means of acquiring novel and valuable information regarding the expression and regulation of genes, under the control of miRNA, involved in mammalian orofacial development. METHODS: To identify differentially expressed miRNAs during mammalian orofacial ontogenesis, miRNA expression profiles from gestation day (GD) -12, -13 and -14 murine orofacial tissue were compared utilizing miRXplore microarrays from Miltenyi Biotech. Quantitative real-time PCR was utilized for validation of gene expression changes. Cluster analysis of the microarray data was conducted with the clValid R package and the UPGMA clustering method. Functional relationships between selected miRNAs were investigated using Ingenuity Pathway Analysis. RESULTS: Expression of over 26% of the 588 murine miRNA genes examined was detected in murine orofacial tissues from GD-12,GD-14. Among these expressed genes, several clusters were seen to be developmentally regulated. Differential expression of miRNAs within such clusters wereshown to target genes encoding proteins involved in cell proliferation, cell adhesion, differentiation, apoptosis and epithelial-mesenchymal transformation, all processes critical for normal orofacial development. CONCLUSIONS: Using miRNA microarray technology, unique gene expression signatures of hundreds of miRNAs in embryonic orofacial tissue were defined. Gene targeting and functional analysis revealed that the expression of numerous protein-encoding genes, crucial to normal orofacial ontogeny, may be regulated by specific miRNAs. Birth Defects Research (Part A), 2010. © 2010 Wiley-Liss, Inc. [source] | ||||||||||