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Results for “endogenous RNA”

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At least 127 records · Page 7Linked to original sources
PubMed2002

Correlation of estrogen beta-receptor messenger RNA with endogenous levels of plasma estradiol and progesterone in the female rat hypothalamus, the bed nucleus of stria terminalis and the medial amygdala.

Estrogen receptor beta (ERbeta) has been previously mapped in the rat central nervous system. This study aims to explore the regulation of ERbeta mRNA as it is expressed in the intact and cycling female rat brain. Young adult female rats (90+ day, N=20) were screened for estrous phases via vaginal cytology and sacrificed. Brains and blood were collected and processed for in situ hybridization and estradiol (E2) and progesterone (P4) hormone assays, respectively. ERbeta mRNA levels exhibited significant correlations with ovarian steroid ratios (E2/P4) in various brain regions, including the bed nucleus of stria terminalis, the medial nucleus of amygdala, and the anteroventral periventricular nuclei but not the paraventricular and the supraoptic nuclei or the preoptic area of the hypothalamus. No regulatory changes were detected in the cortex. Specifically, in the affected regions, higher P4 levels were significantly correlated with higher ERbeta mRNA expression. In contrast, there was a tendency for higher E2 levels to be correlated with lower ERbeta mRNA expression, but this tendency reached significance only in the bed nucleus of stria terminalis. These results suggest that ERbeta mRNA is regulated in the intact and cycling female rat hypothalamic as well as extrahypothalamic brain regions, and the circulating ovarian hormones play a critical role.

Amygdala↗
PubMed2026

Construction of circRNA-miRNA-mRNA regulatory networks in the intestine of turbot (Scophthalmus maximus) following Vibrio anguillarum infection.

Circular RNAs (circRNAs) play pivotal roles in post-transcriptional regulation by acting as molecular sponges for microRNAs (miRNAs) within the competitive endogenous RNA (ceRNA) network. However, the regulatory mechanisms in teleost immune responses remain poorly understood. In this study, circRNA-miRNA-mRNA networks were investigated in turbot (Scophthalmus maximus) following Vibrio anguillarum infection to elucidate host-pathogen interactions. Through high-throughput sequencing of intestinal tissues, a total of 50 differentially expressed circRNAs (DE-circRNAs) (18 at 2 hpi, 16 at 12 hpi, 16 at 48 hpi), 212 DE-miRNAs (11 at 2 hpi, 70 at 12 hpi, 15 at 48 hpi), and 1774 DE-mRNAs were identified. Functional enrichment analyses (GO/KEGG) revealed significant associations with immune pathways, including the MAPK signaling pathway and gap junction. An integrated circRNA-miRNA-mRNA regulatory network was constructed, highlighting key interactions including novel_circ_0002573/DE-miR-27a-3p/FGB and novel_circ_0002423/novel_347/GNE, which may regulate inflammatory and antibacterial responses. The expression patterns of selected circRNAs, miRNAs and mRNAs were validated using qRT-PCR, confirming the reliability of the sequencing results. Importantly, fibrinogen beta chain (FGB) and CXCR4/CXCL12 signaling were identified as critical immune modulators. These findings provide insights of the ceRNA regulatory networks involved in teleost intestinal immunity and provide potential molecular targets for selective breeding of disease resistance in this species.

Animals↗
PubMed1974

Role of DNA-dependent RNA polymerases II and III in transcription of the adenovirus genome late in productive infection.

DNA-dependent RNA polymerases I, II, and III were isolated and partially purified from KB (human) cells 18 hr after infection with adenovirus 2. As reported previously for the enzymes from other animal cells, RNA polymerase II was completely sensitive to low concentrations of alpha-amanitin (50% inhibition at 0.02 mug/ml), RNA polymerase III was completely sensitive to high concentrations of alpha-amanitin (50% inhibition at 20 mug/ml) and RNA polymerase I was totally resistant to concentrations of alpha-amanitin less than or equal to 200 mug/ml. RNA synthesis by the endogenous RNA polymerase activities in nuclei isolated from infected cells was completely sensitive to alpha-amanitin, thus suggesting that RNA polymerase I is not involved in viral DNA transcription even though it is present in these cells. The alpha-amanitin inhibition curve was biphasic and showed inflection points at about 0.02 and 20 mug/ml, suggesting the participation of both RNA polymerases II and III in the synthesis of RNA in these nuclei. Furthermore, at least a large fraction of the synthesis of the nuclear precursors to viral mRNA, monitored by hybridization to viral DNA, showed the same sensitivity to alpha-amanitin as did RNA polymerase II; and the synthesis of both viral 5.5S RNA and (presumably cellular) 5S RNA in the isolated nuclei exhibited the same sensitivity to alpha-amanitin as did purified RNA polymerase III. Thus, these data provide strong supporting evidence for previous studies which suggested the involvement of an RNA polymerase II in transcription of the adenovirus genome and demonstrate the role of an RNA polymerase III activity in the synthesis of viral 5.5S RNA and cellular 5S RNA.

Adenoviridae↗
PubMed1989

Probing Drosophila gene function by antisense RNA.

The conventional technique for assigning a particular genetic function to a cloned transcription unit has relied on the rescue of the mutant phenotype by germ line transformation. An alternative approach is to mimic a mutant phenotype by the use of antisense RNA injections to produce phenocopies. This approach has been successfully used to identify genes involved in early pattern forming processes in the Drosophila embryo. At the time when antisense RNA is injected, the embryo develops as a syncytium composed of about 5000 nuclei which share a common cytoplasm. The gene interactions required to establish the body plan occur before cellularization at the blastoderm stage. Thus the nuclei and their exported transcripts are accessible to the injected antisense RNA. The antisense RNA interferes with the endogenous RNA by an as yet unidentified mechanism. The extent of interference is only partial and produces phenocopies with characteristics of weak mutant alleles. In our lab and others, this approach has been successfully used to identify several genes required for normal Drosophila pattern formation.

Animals↗
PubMed1997

Effect of UVA on RNA synthesis in isolated chicken liver nuclei.

Little information is available on the effects of UVA (320-400 nm radiation) on transcription. We examined the effect of UVA on RNA synthesis in isolated chicken liver nuclei. Nuclei in air or nitrogen were irradiated with UVA, and the RNA synthesis induced by endogenous RNA polymerase was estimated under conditions in which little or no initiation occurs. Incorporation of [3H]UMP into the acid-insoluble fraction was used as the measure of RNA synthesis in the nuclei. In air the amount of synthesized RNA decreased with increasing UVA fluence. In contrast, in nitrogen UVA had little effect on RNA synthesis. Sodium azide and histidine, which effectively scavenge singlet oxygen (1O2) as well as hydroxyl radicals (.OH), protected the nuclei from inhibition of RNA synthesis; whereas, sodium formate and dimethyl sulfoxide, both of which much more effectively scavenge .OH than 1O2, had no protective effect. These findings provide a strong indication that 1O2 is involved in the inhibition of RNA synthesis. In addition, RNA polymerase II-dependent synthesis (in the nucleoplasm) was much more sensitive to UVA than RNA polymerase I-dependent synthesis (in the nucleolus).

Animals↗
PubMed2003

Decreased frequency and highly aberrant spectrum of ultraviolet-induced mutations in the hprt gene of mouse fibroblasts expressing antisense RNA to DNA polymerase zeta.

In the budding yeast Saccharomyces cerevisiae, DNA polymerase zeta (pol zeta) is responsible for the great majority of mutations generated during error-prone translesion replication of DNA that contains UV-induced lesions. The catalytic subunit of pol zeta is encoded by the Rev3 gene. The orthologue of Rev3 has been cloned from higher eukaryotic cells, including human, but its role in mutagenesis and carcinogenesis remains obscure. Investigation into the cellular function of pol zeta has been hindered by the fact that Rev3 knockout mice do not survive beyond midgestation, and embryonic stem cells used to derive these mice are not genetically stable. We have generated a transgenic mouse that expresses antisense RNA transcripts to mRev3 endogeneous RNA. These mice are viable, have greatly reduced levels of Rev3 transcript, and have reduced levels of B cells and impaired development of high-affinity memory B cells. Here, we report that exposure of fibroblasts derived from these mice to UV resulted in a 4-5-fold reduction in mutant frequency at the hprt locus at every dose examined, and the mutation spectrum was highly aberrant compared with the control cells. In the control cells, 80% of the mutations were transitions and approximately 75% of these arose from photoproducts in the putative leading strand template. Strikingly, in transgenic cells, most of the mutations were transversions and there was a complete loss of strand bias. This mutation spectrum is highly aberrant and is similar to that induced by UV in human xeroderma pigmentosum variant cells, which lack polymerase eta. These data indicate that most UV-induced mutations are dependent on DNA pol zeta, a function that has been conserved from yeast to higher eukaryotic cells. However, in mammalian cells, other DNA polymerase(s) may accomplish error-prone translesion replication and are responsible for residual UV mutagenesis observed in the absence of pol zeta. Further, these data support a central role for DNA polymerase eta in the error-free bypass of UV photoproducts. The antisense Rev3 mice should be a useful model to study mutagenic lesion bypass by pol zeta in mammalian cells and to investigate the role this polymerase plays in carcinogenesis.

Animals↗
PubMed1995

Reverse transcription in a macromolecular complex of ovine bone marrow: possible involvement in the antigen receptor mediated signal transduction process.

A macromolecular fraction was isolated from ovine bone marrow and designated the active fraction (AF). Two distinct enzymatic activities were detected in the AF: (1) a RNA-dependent RNA polymerase, and (2) a reverse transcriptase. RNA polymerase uses an endogenous RNA molecule of the AF as the template while the product of this RNA polymerase reaction forms the template for the reverse transcriptase. Synthetic reactions are initiated exclusively upon the exposure of the in vitro system to one of the external proteins, selected at random, ovalbumin or insulin. Ovalbumin specific (OS) and insulin specific (IS) AF fractions were prepared. OS-AF binds 14C-ovalbumin and the IS-AF binds 14C-insulin, but not vice versa. Reverse transcription activity of OS-AF is stimulated only upon its exposure to ovalbumin and not to insulin while the reverse is true for the activity associated with IS-AF. Indirect evidence indicates that the enzymes which synthesize nucleic acids are closely associated with the antigen receptor on the B-lymphocyte plasma membrane, the mlgM, and that the antigen binding to its receptor helps in the activation of these enzymes.

Animals↗
PubMed1973

Primate RNA tumor virus-like DNA synthesized endogenously by RNA-dependent DNA polymerase in virus-like particles from fresh human acute leukemic blood cells.

A particle of discrete biochemical composition was purified from fresh, unfrozen peripheral blood leukocytes of human patients with acute myeloblastic leukemia. This particle endogenously synthesized DNA by use of an RNA primer and template. About half of the DNA sequences synthesized in the presence of actinomycin D hybridized to RNA isolated from type-C sarcoma viruses of primates or mice; lower annealing values were obtained with RNA isolated from other sarcoma or leukemia viruses. The results confirm and extend previous results from molecular hybridization experiments related to the existence in human leukemia of components of RNA tumor viruses.

Adult↗
PubMed1977

Selective and accurate transcription of the Xenopus laevis 5S RNA genes in isolated chromatin by purified RNA polymerase III.

Chromatin isolated from immature oocytes was found to contain an endogenous RNA polymerase activity (RNA nucleotidyltransferase; nucleoside triphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) that synthesizes predominately 5S RNA. However, the levels of total RNA synthesis and 5S RNA synthesis in chromatin were each stimulated 10- to 50-fold by an exogenous RNA polymerase III purified from X. laevis oocytes. The 5S genes in chromatin were transcribed by the exogenous enzyme in a highly selective (3000-fold above random) and predominately asymmetric fashion. A significant fraction of 5S RNA sequences were also found in a discrete transcript, approximately 5S in size. Total RNA synthesis was significantly stimulated when chromatin was transcribed by oocyte RNA polymerase I, murine RNA polymerase II, and low levels of Escherichia coli RNA polymerase. However, these enzymes did not significantly stimulate 5S RNA synthesis above the endogenous levels. Both homologous oocyte RNA polymerase I and III and E. coli RNA polymerase transcribed the 5S genes in deproteinized DNA to approximately the same extent (severalfold above random) and both the sense and anti-sense strands of the gene were transcribed. It appears, therefore, that both chromatin-associated components and a purified RNA polymerase III are necessary and sufficient for the selective and accurate transcription of the 5S RNA genes in vitro.

Animals↗
PubMed1976

Effect of Sarkosyl on chromatin and viral RNA synthesis. The isolation of SV40 transcription complex.

The endogenous RNA polymerase activity of mouse nucleic is enhanced several-fold by the anionic detergent Sarkosyl. The action of Sarkosyl is exerted primarily on the alpha-amanitin sensitive form of the enzyme. This detergent causes the release of nearly all the protein associated with cellular DNA but does not release initiated RNA polymerase. Sarkosyl was also able to activate the RNA polymerase activity from mitotic cells, in which transcription of the highly condensed chromatin is minimal. The use of this anionic detergent has also permitted the extraction of a nucleoprotein complex from Simian Virus 40 (SV40) infected monkey cells. Molecular hybridization experiments have established the viral specificity of the RNA synthesized in vitro by the endogenous polymerase present in this complex.

Animals↗