Showing papers on "RNA-induced transcriptional silencing published in 1984"
TL;DR: The RNA sequences derived from an analysis of eight U7 cDNA clones show neither homologies nor complementarities to any other know U‐RNAs, suggesting a unique hybrid structure for a processing intermediate formed from histone precursor and U7 RNA.
Abstract: 3' Processing of sea urchin H3 histone pre-mRNA depends on a small nuclear RNP which contains an RNA of nominally 60 nucleotide length, referred to below as U7 RNA. The U7 RNA can be enriched by precipitation of sea urchin U-snRNPs with human systematic lupus erythematosus antiserum of the Sm serotype. We have prepared cDNA clones of U7 RNA and determined by hybridization techniques that this RNA is present in sea urchin eggs at 30-fold lower molar concentration than U1 RNA. The RNA sequences derived from an analysis of eight U7 cDNA clones show neither homologies nor complementarities to any other know U-RNAs. The 3' portion of the presumptive RNA sequence can be folded into a stem-loop structure. The 5'-terminal sequences would be largely unstructured as free RNA. Their most striking feature is their base complementarity to the 3' conserved sequences of histone pre-mRNAs. Six out of nine bases of the conserved CAAGAAAGA sequence of the histone mRNA precursor and 13 out of 16 nucleotides from the conserved palindrome can be base paired with presumptive U7 RNA sequence, suggesting a unique hybrid structure for a processing intermediate formed from histone precursor and U7 RNA.
136 citations
TL;DR: It is demonstrated that the immediate 5' flanking region sequences are a highly specific hydridization probe capable of distinguishing U1 RNA true genes from pseudogenes.
123 citations
TL;DR: An in situ hybridization method for detecting cellular RNAs in tissue sections using methacrylate as the embedding medium and offers the advantage of superior morphological preservation compared with previously published procedures is presented.
Abstract: We present an in situ hybridization method for detecting cellular RNAs in tissue sections using methacrylate as the embedding medium. The technique offers the advantage of superior morphological preservation compared with previously published procedures. Since sections can be cut 1 micron or less in thickness, full advantage is taken of the short path length of 3H electrons. Applying this procedure to developing amphibian oocytes, we investigated the accumulation and localization of RNA complementary to the histone genes and their adjacent spacers. Histone RNA begins to accumulate in the cytoplasm of late pachytene-early diplotene oocytes, rapidly reaching a maximum concentration during Dumont stage 1. After this stage the concentration of histone RNA declines. RNA transcribed from histone coding regions is located almost exclusively in the cytoplasm of oocytes. Transcripts of the spacer regions, which are known to be synthesized on oocyte lampbrush chromosomes, do not accumulate in the oocytes. [3H]RNA complementary to U2 small nuclear RNA, used in these experiments as a control, hybridized predominantly to the nucleus of the oocytes.
71 citations
TL;DR: The results of these experiments clearly indicate that a normal rate of nucleolar RNA synthesis, and anormal rate of accumulation of total cellular RNA are not a prerequisite for the entry of cells into S phase.
42 citations
TL;DR: This study was able to identify two distinct classes of polyadenylated nuclear RNA, which were differentiated with respect to whether or not they were associated with other RNA molecules, and demonstrated for the first time that small nuclear RNA-heterogeneous nuclear RNA hybrids can be isolated without crosslinking and that proteins are not necessary to stabilize the complexes.
11 citations