RNA

About: RNA is a research topic. Over the lifetime, 111695 publications have been published within this topic receiving 5475262 citations. The topic is also known as: ribonucleic acid.

Complete nucleotide sequence of SV40 DNA

Abstract: The determination of the total 5,224 base-pair DNA sequence of the virus SV40 has enabled us to locate precisely the known genes on the genome. At least 15.2% of the genome is presumably not translated into polypeptides. Particular points of interest revealed by the complete sequence are the initiation of the early t and T antigens at the same position and the fact that the T antigen is coded by two non-contiguous regions of the genome; the T antigen mRNA is spliced in the coding region. In the late region the gene for the major protein VP1 overlaps those for proteins VP2 and VP3 over 122 nucleotides but is read in a different frame. The almost complete amino acid sequences of the two early proteins as well as those of the late proteins have been deduced from the nucleotide sequence. The mRNAs for the latter three proteins are presumably spliced out of a common primary RNA transcript. The use of degenerate codons is decidedly non-random, but is similar for the early and late regions. Codons of the type NUC, NCG and CGN are absent or very rare.

Roles of the Mammalian Mitochondrial Fission and Fusion Mediators Fis1, Drp1, and Opa1 in Apoptosis

Abstract: During apoptosis, the mitochondrial network fragments. Using short hairpin RNAs for RNA interference, we manipulated the expression levels of the proteins hFis1, Drp1, and Opa1 that are involved in...

Identification of essential genes in cultured mammalian cells using small interfering RNAs.

Abstract: We report the first RNAi-induced phenotypes in mammalian cultured cells using RNA interference mediated by duplexes of 21-nt RNAs. The 21 gene products studied have different functions and subcellular localizations. Knockdown experiments monitored by immunofluorescence and immunoblotting show that even major cellular proteins such as actin and vimentin can be silenced efficiently. Genes were classified as essential or nonessential depending on impaired cell growth after RNA silencing. Phenotypes also involved altered cell morphology and aberrant mitotic arrest. Among the essential genes identified by RNAi for which such information was previously not available are lamin B1, lamin B2, NUP153, GAS41, ARC21, cytoplasmic dynein, the protein kinase cdk1 and both beta- and gamma-actin. Newly defined nonessential genes are emerin and zyxin. Several genes previously characterized by other methods such as knockout of murine genes are included as internal controls and gave identical results when RNAi was used. In the case of two nonessential genes (lamin A/C and zyxin) RNAi provides a recognizable phenotype. Our results complete the characterization of the mammalian nuclear lamins. While lamins A/C appear as nonessential proteins in the mouse embryo and in RNAi treated cultured cells, the two other lamins, B1 and B2, are now identified as essential proteins. Interestingly the inner nuclear membrane protein emerin, thought to be a ligand of lamin A/C, is also a nonessential protein in tissue culture cells.

Purification of RNA using TRIzol (TRI reagent).

Abstract: TRIzol solubilization and extraction is a relatively recently developed general method for deproteinizing RNA. This method is particularly advantageous in situations where cells or tissues are enriched for endogenous RNases or when separation of cytoplasmic RNA from nuclear RNA is impractical. TRIzol (or TRI Reagent) is a monophasic solution of phenol and guanidinium isothiocyanate that simultaneously solubilizes biological material and denatures protein. After solubilization, the addition of chloroform causes phase separation (much like extraction with phenol:chloroform:isoamyl alcohol), where protein is extracted to the organic phase, DNA resolves at the interface, and RNA remains in the aqueous phase. Therefore, RNA, DNA, and protein can be purified from a single sample (hence, the name TRIzol). TRIzol extraction is also an effective method for isolating small RNAs, such as microRNAs, piwi-associated RNAs, or endogeneous, small interfering RNAs. However, TRIzol is expensive and RNA pellets can be difficult to resuspend. Thus, the use of TRIzol is not recommend when regular phenol extraction is practical.