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The Functions Of Animal Micrornas., Victor Ambros

Victor R. Ambros

MicroRNAs (miRNAs) are small RNAs that regulate the expression of complementary messenger RNAs. Hundreds of miRNA genes have been found in diverse animals, and many of these are phylogenetically conserved. With miRNA roles identified in developmental timing, cell death, cell proliferation, haematopoiesis and patterning of the nervous system, evidence is mounting that animal miRNAs are more numerous, and their regulatory impact more pervasive, than was previously suspected.

Growth Rate Gradients And Extracellular Ph In Roots: How To Control An Explosion, Winfried S. Peters

Winfried S. Peters

Expression Profiling Of Mammalian Micrornas Uncovers A Subset Of Brain-Expressed Micrornas With Possible Roles In Murine And Human Neuronal Differentiation., Lorenzo F. Sempere, Sarah Freemantle, Ian Pitha-Rowe, Eric Moss, Ethan Dmitrovsky, Victor R. Ambros

Victor R. Ambros

Background The microRNAs (miRNAs) are an extensive class of small noncoding RNAs (18 to 25 nucleotides) with probable roles in the regulation of gene expression. In Caenorhabditis elegans, lin-4 and let-7 miRNAs control the timing of fate specification of neuronal and hypodermal cells during larval development. lin-4, let-7 and other miRNA genes are conserved in mammals, and their potential functions in mammalian development are under active study. Results In order to identify mammalian miRNAs that might function in development, we characterized the expression of 119 previously reported miRNAs in adult organs from mouse and human using northern blot analysis. Of …

A Short History Of A Short Rna, Victor Ambros, Rosalind Lee, Rhonda Feinbaum

Victor R. Ambros

Comment on: The C. elegans heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14. [Cell. 1993]

Immunity Regulatory Dnas Share Common Organizational Features In Drosophila, Kate Senger, Grant W. Armstrong, William J. Rowell, Jennifer M. Kwan, Michele Markstein, Michael Levine

Michele Markstein

Infection results in the rapid activation of immunity genes in the Drosophila fat body. Two classes of transcription factors have been implicated in this process: the REL-containing proteins, Dorsal, Dif, and Relish, and the GATA factor Serpent. Here we present evidence that REL-GATA synergy plays a pervasive role in the immune response. SELEX assays identified consensus binding sites that permitted the characterization of several immunity regulatory DNAs. The distribution of REL and GATA sites within these DNAs suggests that most or all fat-specific immunity genes contain a common organization of regulatory elements: closely linked REL and GATA binding sites positioned …

Identification Of Micrornas And Other Tiny Noncoding Rnas By Cdna Cloning, Victor Ambros, Rosalind Lee

Victor R. Ambros

MicroRNAs (miRNAs) and other small RNAs can be identified by cloning and sequencing cDNAs prepared from the ∼22-nt fraction of total RNA. Methods are described for the construction of cDNA libraries from small noncoding RNAs through the use of T4 RNA ligase, reverse transcriptase, and polymerase chain reaction. cDNAs are cloned in λ or plasmid vectors, and the sequences are compared to annotated genomic sequence databases, and analyzed by RNA folding programs to distinguish miRNA sequences from other small RNAs of similar size. Northern blot hybridization is used to confirm the expression of small RNAs in vivo.