Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To gain insight into the mechanisms involved in the formation of maternally stored mRNPs during Xenopus laevis development, we searched for soluble cytoplasmic proteins of the oocyte that are able to selectively bind mRNAs, using as substrate radiolabeled mRNA. In vitro mRNP assembly in solution was followed by UV-cross-linking and RNase digestion, resulting in covalent tagging of polypeptides by nucleotide transfer. Five polypeptides of approximately 54, 56 60, 70, and 100 kD (p54, p56, p60, p70, and p100) have been found to selectively bind mRNA and assemble into mRNPs. These polypeptides, which correspond to previously described native mRNP components, occur in three different particle classes of approximately 4.5S, approximately 6S, and approximately 15S, as also determined by their reactions with antibodies against p54 and p56. Whereas the approximately 4.5S class contains p42, p60, and p70, probably each in the form of individual molecules or small complexes, the approximately 6S particles appears to consist only of p54 and p56, which occur in a near-stoichiometric ratio suggestive of a heterodimer complex. The approximately 15S particles contain, in addition to p54 and p56, p60 and p100 and this is the single occurring form of RNA-binding p100. We have also observed changes in the in vitro mRNA binding properties of these polypeptides during oogenesis and early embryonic development, in relation to their phosphorylation state and to the activity of an approximately 15S particle-associated protein kinase, suggesting that these proteins are involved in the developmental translational regulation of maternal mRNAs.
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PMID:Different forms of soluble cytoplasmic mRNA binding proteins and particles in Xenopus laevis oocytes and embryos. 167 Jul 77

Short-term cultures of cells from human rain tumours have been reported to synthesise RNA particles of density in the range characteristic of C type RNA retroviruses, with associated DNA polymerase activity. Fresh tumour cells obtained from 6 children with astrocytoma and 7 children with medulloblastoma, together with one sample of normal brain tissue and normal leukocytes from brain tumour patients were assayed by several characteristics for the primate retrovirus. 1 or 6 (17%) astrocytomas and 4 of 7 (57%) medulloblastomas released RNA particles which banded in sucrose gradients at a density of 1.16-1.18 g/cm3 together with a short segment of DNA, which was eliminated by prior ribonuclease treatment and two proteins of 28k and 16k daltons. These findings were compatible with the presence of a primate retrovirus. Immune coprecipitation of 125I-labelled proteins from the 1.16-1.18 g/cm3 gradient region failed to show any reactivity with antisera to p28 core antigens or the p70 reverse transcriptase antigens of simian sarcoma virus, baboon endogenous virus or Mason Pfizer virus. Assays for DNA polymerase activity in culture supernatant fluid showed only a low amount of activity with template preferences not characteristic of the retroviral reverse transcriptase enzyme.
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PMID:Children's brain tumour cells produce RNA particles with incomplete retrovirus characteristics. 628 9

Interleukin-12 (IL-12) production by human monocytes is stringently regulated through the inducibility of both subunits, p35 and p40, and expression of p35 mRNA is the limiting factor for the secretion of the bioactive IL-12 p70 heterodimer. Optimal induction of p35 mRNA requires priming of the monocytes by interferon-gamma (IFN-gamma), followed by brief exposure to lipopolysaccharide or other bacterial products. To investigate control of p35 gene expression, we isolated genomic clones containing the human p35 gene and determined the 5' end of the mRNA expressed in monocytes. We discovered that a unique p35 transcript is induced in monocytes that begins downstream of a consensus TATA box that lies within the 5' end of the cDNA originally cloned from Epstein-Barr virus (EBV)-transformed B cells. Analysis of p35 mRNA by Northern blotting showed that the message from monocytes is approximately 200 bases shorter than message derived from the EBV-transformed B-cell line VDS. The initiation sites downstream from the TATA box were confirmed by RNase protection and 5' RACE. The data indicate that p35 transcription can initiate from different sites depending on the cell type and that the shorter inducible transcript in monocytes is the one that accumulates after stimulation. Protein translation of these two forms may result in proteins of different sizes with potential implications for the regulation of IL-12 secretion and function.
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PMID:Interferon-gamma-dependent inducible expression of the human interleukin-12 p35 gene in monocytes initiates from a TATA-containing promoter distinct from the CpG-rich promoter active in Epstein-Barr virus-transformed lymphoblastoid cells. 961 61

During brain maturation, histone H1(0) accumulates in both nerve and glial cells. The expression of this "linker" histone, the role of which still remains unclear, is a complex process, having both transcriptional and post-transcriptional regulatory components. In particular, the expression of H1(0) in rat cortical neurons is regulated mainly at the post-transcriptional level, and unknown cellular proteins are likely to affect H1(0) mRNA stability and/or translation. In looking for such factors, we tested the ability of rat brain extracts to protect H1(0) RNA probe from degradation by T1 RNase. The results reported here demonstrate that rat brain contains at least one major (p40) and two minor (p110 and p70) binding factors, specific for H1(0) RNA, all of which are much more or exclusively expressed in adult rat brain, when compared with other tissues. The binding of the factors is confined to a portion of the 3'-untranslated region (3'-UTR), which is highly conserved among murine and human H1(0) mRNAs. These findings suggest that the proteins identified play a critical role in regulating the expression of H1(0) histone in the brain of mammals.
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PMID:H1(0) RNA-binding proteins specifically expressed in the rat brain. 971 12

The objective of this study was to investigate the impact of feeding mice a diet rich in n-3 polyunsaturated fatty acids (PUFA) from fish oil on the interleukin-12 (IL-12) and interferon-gamma (IFNgamma) production during the early stage of an infectious challenge with Listeria monocytogenes. Weanling female C3H/HeN mice were fed AIN-93G experimental diets containing 20%, by weight one of three fat sources: lard (low PUFA), soybean oil (n-6 PUFA) or a mixture (9:1) of menhaden fish oil and corn oil (n-3 PUFA). After 4 weeks, mice were injected intraperitoneally with 10(5) Listeria monocytogenes and the concentration of IL-12(p70) and IFNgamma in serum was determined 24 h post-infection by ELISA. IL-12p35, IL-12p40 mRNA, and IFNgamma mRNA in the spleen were quantified by RNase protection assay. The number of IFNgamma-producing cells in the spleen was determined by flow cytometry using an intracellular staining procedure. We found that n-3 PUFA-fed mice had lower levels of circulating IL-12 at 24 h post-infection than n-6 PUFA- or low PUFA-fed mice (9.7+/-3.4 pg/ml vs. 61.6+/-10.6, and 44.4+/-12.5 pg/ml, respectively; P=0.002, n = 10/trt). The level of IL-12 p35 mRNA did not significantly differ among dietary treatment groups. However, IL-12p40 mRNA was significantly lower in n-3 PUFA- and n-6 PUFA-fed mice compared to low-PUFA-fed mice. Further, the n-3 PUFA group also had the lowest circulating IFNgamma (4.4+/-1.8 ng/ml vs. 9.1+/-1.0, and 9.7+/-2.1 ng/ml, respectively; P = 0.007. n = 8-10/trt). The n-3 PUFA-fed mice had significantly lower IFNgamma mRNA in their spleens compared to the mice fed the other fat sources. In agreement with having lower circulating IFNgamma and lower splenic IFNgamma mRNA, n-3 PUFA-fed mice had a significantly lower percentage of IFNgamma-producing cells in their spleens compared with the n-6 PUFA-fed group (2.1+/-0.6 vs. 4.2+/-0.7%; P = 0.037, n = 10/trt). In summary, feeding mice a diet rich in n-3 PUFA from fish oil significantly lowered the production of both IL-12 and IFNgamma during the early phase of a Listeria infection.
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PMID:Dietary omega-3 polyunsaturated fatty acids from fish oil reduce interleukin-12 and interferon-gamma production in mice. 1006 39

Interleukin-12 (IL-12) is a monocyte/macrophage-derived cytokine that plays a prominent role in the development of T helper type 1 (Th1) cell-mediated immune responses. Glycyrrhizin (GL), an aqueous extract of liquorice root, used as Chinese medicine, is known to have various immunomodulating activities. In this study, GL showed a dose-dependent priming effect on lipopolysaccharide (LPS)-induced IL-12 p40 and IL-12 p70 (heterodimer of p40 and p35) protein production by peritoneal macrophages (PM). The maximal effect was observed when GL was intraperitoneally administered 12 hr before the PM were harvested and stimulated in vitro with LPS. The increases in IL-12 p70 and p40 protein production were primarily due to up-regulated transcription of IL-12 p35 and p40 messenger RNAs (mRNAs), as demonstrated by RNase protection assay. The augmentation of IL-12 p40 mRNA expression induced by GL pretreatment was associated with increased NF-kappaB activation. Moreover, GL exhibited the same priming effect on IL-12 production in interferon-gamma knockout (IFN-gamma-/-) mice. The production of granulocyte-macrophage colony-stimulating factor (GM-CSF) was not induced at any time point after GL pretreatment. These findings demonstrated the ability of GL to enhance LPS-induced IL-12 production by peritoneal macrophages, and indicated that the priming effect of GL on IL-12 production was independent of both IFN-gamma and GM-CSF.
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PMID:Glycyrrhizin enhances interleukin-12 production in peritoneal macrophages. 1141 11

Post-transcriptional regulation of mRNA metabolism is involved in processes as different as cell fate specification in development and cell response to a large variety of environmental cues. Regulation of all steps of RNA metabolism depends on RNA-binding proteins (RBPs). By using a T1 RNase-protection assay, we previously identified three H1 degrees RNA-binding factors (p40, p70 and p110), highly expressed in the rat brain. Here we report enrichment of these factors from brain extracts, obtained by affinity chromato-graphy of biotinylated H1 degrees RNA-protein complexes on streptavidin-conjugated paramagnetic particles. The purified proteins maintain RNA-binding ability and preference for histone messages.
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PMID:Purification by affinity chromatography of H1o RNA-binding proteins from rat brain. 1263 6

Interleukin-12 (IL-12), an important cytokine in host defense against microbial pathogens, regulates natural killer and T-cell function(s) including the induction of gamma-interferon production. The major cellular sources of IL-12 are monocytes/macrophages. Bacteria, bacterial products, and intracellular parasites are the most efficient inducers of IL-12 production. In the present study we show that a signal transduction pathway sensitive to rapamycin may have an important role in the regulation/suppression of Staphylococcus aureus-induced IL-12 production in vitro. Human peripheral blood mononuclear cells, monocytes, or a human monocytic cell line THP-1 were stimulated with S. aureus Cowan strain 1 (SAC) in the presence or absence of rapamycin and investigated for production of IL-12 protein by enzyme-linked immunosorbent assay and IL-12 p40 mRNA accumulation by RNase protection assay or real-time quantitative polymerase chain reaction. The results show that rapamycin significantly enhances SAC-induced IL-12 p70 protein production and IL-12 p40 mRNA accumulation. Further the results demonstrate that wortmannin enhances SAC-induced IL-12 p40 mRNA accumulation, whereas Ly294002 does not. These data indicate that a rapamycin-sensitive signaling pathway may act as a negative feedback cascade in the regulatory mechanisms of IL-12 production.
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PMID:Negative regulation of interleukin-12 production by a rapamycin-sensitive signaling pathway: a brief communication. 1453 May 10