MicroRNA-Directed-Cleavage-of-HOXB8-mRNA课件.ppt

MicroRNA-Directed MicroRNA-Directed Cleavage of Cleavage of HOXB8 HOXB8 mRNAmRNASoraya Yekta,I-hung Shih,David P.BartelSoraya Yekta,I-hung Shih,David P.Bartel 23 APRIL 2004 VOL 304 SCIENCE23 APRIL 2004 VOL 304 SCIENCE23 APRIL 2004 VOL 304 SCIENCE23 APRIL 2004 VOL 304 SCIENCE Hox genes in mammals1)The vertebrate homeotic complex comprises four distinct Hox gene clusters(Hox A,B,C,D)that are organized into thirteen homology 2)The chromosomal organization of the genes in each Hox cluster reflects its anterior-posterior expression in the body plan(spatial colinearity).3)In general,members of the same subgroup are expressed at the same time and have the same anterior boundary of expressionThe current model for the biogenesis and post-transcriptional suppression of microRNAs and siRNAs Recent progressnIn plant,most miRNAs anneal to their targets with nearly complete complementarity at a single site,leading to mRNAs cleavage and degradationnThe extent of complementarity between the siRNA/miRNA and its target can determine the mechanism of silencingThe sequence and genomic context of the vertebrate miR-196 familyBold:residues of the mature miRNA;Red:miRNAs validated by cloning.Asterisks:perfectly conserved residuesOverview of the 5 RACE Procedure RNAse protection assayMiR-196directed cleavage of MiR-196directed cleavage of HOXB8 HOXB8 mRNA(1)mRNA(1)blackblack Absolutely conserved nucleotides;Absolutely conserved nucleotides;redred complementary site;complementary site;pinkpink G:U wobbleG:U wobble MiR-196directed cleavage of MiR-196directed cleavage of HOXB8 HOXB8 mRNA(2)mRNA(2)perfect antisense sequence of miR-196a:miR-196a-as perfect antisense sequence of miR-196a:miR-196a-as perfect antisense sequence of miR-1d:miR-1d-asperfect antisense sequence of miR-1d:miR-1d-asmiR-1d expressed in skeletal muscle cells miR-1d expressed in skeletal muscle cells Additional HOX genes predicted to be Additional HOX genes predicted to be regulatory targets of miR-196(1)regulatory targets of miR-196(1)Wide red barsWide red bars extensive complementarity,narrow barsnarrow bars seed matches,AsterisksAsterisks slightly relaxed seed matches that permit G:U wobbleAdditional HOX genes predicted to be Additional HOX genes predicted to be regulatory targets of miR-196(2)regulatory targets of miR-196(2)Additional HOX genes predicted to be Additional HOX genes predicted to be regulatory targets of miR-196(3)regulatory targets of miR-196(3)Thank you!