Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nonhistone acidic proteins were isolated, by equilibrium density centrifugation in 4 M cesium chloride, from the chromatin isolated and purified from the uterus of the ovariectomized rat or from calf endometrium. Evidence is presented to show (1) that arginine-rich histones are more effective inhibitors of chromatin-directed RNA synthesis in vitor than lysine-rich histones, (2) that the nonhistone acidic proteins of chromatin do not inhibit the synthesis of RNA directed by chromatin in vitro, (3) that added nonhistone acidic chromatin proteins effect a restoration of histone-inhibited RNA synthesis directed by chromatin in vitro, and (4) that the synthesis of nonhistone acidic chromatin proteins is under estrogen control in the uterus, but not in the liver. It is concluded that a major feature of the early action of estrogen in the uterus of the ovariectomized rat is the stimulation of synthesis and the accumulation in the interphase chromosomes of nonhistone acidic proteins which counter the inhibitory effect of histone on transcription by RNA polymerase. Presumably this would permit more and perhaps a new synthesis of RNA programmed for transport to the cytoplasm.
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PMID:Role of chromatin in estrogen action in the uterus. II. Hormone-induced synthesis of nonhistone acidic proteins which restore histone-inhibited DNA-dependent RNA synthesis. 525 38

The effect of testosterone on transcription was investigated in the uterus of the ovariectomized rat. Testosterone rapidly depressed both RNA polymerase A and B activities for up to 2 h after administration. Thereafter, RNA polymerase A activity increased, reaching control values at 4 h, and remained constant. On the contrary, RNA polymerase B activity remained depressed at 6 and 18 h after the administration of testosterone. The cellular entities or mechanisms which testosterone uses to alter transcription in the cell nucleus remain to be determined.
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PMID:Action of testosterone on RNA synthesis in the rat uterus. 618 10

The administration of 10 micrograms oestradiol to the foetus of the guinea-pig (55-65 days of gestation) causes an increase in RNA polymerase I and II activities in the nuclei of the foetal uterus. RNA polymerase I activity increased by 4 times above the control values after 120 min (p less than 0.001) whereas RNA polymerase II activity increased more rapidly, reaching 2.5 times the control levels at 30 min and 4 times by 120 min after treatment (p less than 0.01).
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PMID:Effect of oestradiol on RNA polymerase of foetal guinea-pig uterus. 683 1

The effect of progesterone on transcription was investigated in the uterus of the ovariectomized rat. Progesterone rapidly depressed both RNA polymerase A and B activities for up to 6 h after steroid administration. Both enzyme activities returned to control values 24 h after steroid treatment. In contrast, in the estrogen-primed rat uterus, progesterone was capable of stimulating RNA polymerase B activity 30 min after hormone treatment. The cellular entities or mechanisms which progesterone uses to alter transcription in cell nucleus remain to be determined.
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PMID:The effect of progesterone on RNA polymerases in the rat uterus. 732 84

Preliminary evidence has indicated that the number of nuclear bodies in uterine luminal epithelial cells of the immature rat may be related to the duration of nuclear retention of the estrogen receptor complex (Clark et al., 1978). To test this hypothesis, an ultrastructural analysis of nuclear and cytoplasmic differentiation was performed at 4, 12, 24, 48, and 72 hr after a single injection of estradiol or nafoxidine (synthetic estrogen agonist/antagonist) into 21 day female rats. Variations in nuclear and cytoplasmic differentiation and in the frequency of occurrence of nuclear bodies (simple and complex) were determined and compared with established biochemical changes in the concentration of nuclear estrogen receptor and RNA polymerase activity (Clark et al., 1978). Following nafoxidine there is sustained elevation of the nuclear concentration of the estrogen receptor as well as RNA polymerase I and II activities over the entire 72-hr period. From 4 to 72 hr the height of the luminal epithelial cell as well as the frequency of nuclear bodies increase at linear rates. Through steady expansion of the cytoplasmic membrane system (RER) and Golgi) the relatively undifferentiated epithelial cells of the control uterus are converted progressively into ones equipped for protein secretion. At 72 hr the effects of an estradiol implant resemble closely those observed after a single injection of nafoxidine; these include sustained nuclear receptor occupancy, elevated RNA polymerase activity, epithelial hypertrophy, and high frequency of nuclear bodies. However, after a single injection of estradiol, the luminal epithelial cells become slightly but significantly taller than the control cells and remain close to this size from 24 to 72 hr.; the frequency of nuclear bodies decreases linearly from 4 to 72 hr to fall below the control level. In addition, limited cytoplasmic autolysis is evident from 24 to 72 hr. A single injection of estradiol results in short-term nuclear receptor occupancy and elevated RNA polymerase activities which return to control levels by 24 hr. This collective evidence offers further support to the hypothesis that the duration of nuclear occupancy by the estrogen receptor is reflected in the size of the nuclear body populations in these epithelial target cells. Also during hyperestrogenization, epithelial hypertrophy is accompanied by steady formation of nuclear bodies.
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PMID:Nuclear bodies as structural indicators of estrogenic stimulation in uterine luminal epithelial cells. 734 May 72

The antioestrogens clomiphene and tamoxifen exhibit both agonistic and antagonistic properties in the rat uterus. The effect of these antioestrogens on RNA polymerase activities in the rat uterus was investigated. Both compounds stimulated an early increase in the activity of endogenous RNA polymerase B similar to that observed after oestradiol treatment. A secondary stimulation of activity of RNA polymerase B was observed after treatment with oestradiol and both antioestrogens. In addition, the activity of endogenous RNA polymerase A was increased initially at 1 h by all three compounds but this activity was maintained at 24 h only by oestradiol.
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PMID:Clomiphene and tamoxifen action in the rat uterus. 741 Oct 13

1. To identify and isolate cDNAs encoding rat and human bradykinin-B2 receptor subtypes we isolated a human bradykinin receptor cDNA homologous to a rat B2 receptor cDNA. 2. The cDNA was expressed in the bradykinin receptor negative cell line, CHO; membranes prepared from these cells bound bradykinin and had specificity similar to that of the known rat B2 receptor. In addition, the expressed receptor has a low affinity for des-Arg9-bradykinin. Thus, the cDNA encodes a human B2-bradykinin receptor. 3. Comparison of the human and rat cDNAs suggested that the human and rat genes are composed of three exons. Cloning, sequencing and characterization of parts of the human and rat B2-bradykinin receptor genes demonstrated the postulated three-exon structure. This structure includes two 5' exons upstream of the most favorable translation initiation methionine in exon-3. 4. The two 5' exons each contain methionines, which if independently spliced to the third exon, would yield an open reading frame that includes all of exon-3. This arrangement could thus vary the amino-terminal region of the protein. Do these potential arrangements occur in human RNAs, and will they lead to proteins with differing amino-termini? 5. Reverse transcriptase-polymerase chain reactions (RT-PCR) using human mRNA, nested primers from exon-1 and exon-3, and detection of the products by hybridization using an independent exon-1 oligonucleotide showed that the arrangement of exon-1 with exon-2 and exon-3 could not be detected in eight human RNAs. Furthermore, exon-1 spliced with exon-3 was a common arrangement. 6. Low stringency examination of human and rat Southern blots revealed only bands attributable to the known human or rat B2-bradykinin receptor. 7. Reduced stringency hybridization searches of seven different genomic and cDNA libraries--including two different human genomic libraries, a rat genomic library, two different rat uterus cDNA libraries, a rat brain library and a human lung library--yielded only rat or human B2-bradykinin receptors. The results of our low stringency hybridization experiments suggest that other bradykinin receptors are less than 60% identical, on the nucleotide level, to the known B2 receptor. 8. Degenerate polymerase chain reactions using rat genomic DNA as a template and degenerate primers, designed based on the homology of a B2-bradykinin receptor with angiotensin-II type-1 receptor, identified B2-bradykinin receptors, angiotensin-II-type-1 receptors and three novel orphan receptors.
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PMID:Bradykinin-B2 receptors in humans and rats: cDNA structures, gene structures, possible alternative splicing, and homology searching for subtypes. 753 72

The fibronectin receptor, alpha 5 beta 1, may be involved in many aspects of early development, including migration of endodermal and mesodermal cells during formation of the placenta, trophoblastic outgrowth in culture, and development of an invasive phenotype by fetal cytotrophoblasts. In contrast to the human blastocyst, the bovine blastocyst elongates in the uterine lumen for several days until it begins attachment, and the fetal trophoblast limits its invasion to the maternal epithelium. Fibronectin receptor expression was characterized in bovine embryos before and after their attachment to the uterus. Initially, the polymerase chain reaction (PCR) was conducted with degenerate oligonucleotide primers to isolate bovine cDNAs for the alpha 5 and beta 1 subunits. Bovine-specific primers were then constructed to assay for alpha 5 and beta 1 mRNA expression in embryo RNA during the morula through the attachment stages using reverse-transcriptase PCR. Northern blot analysis was used to quantify mRNA levels from Days 15 to 21. Integrin and fibronectin protein expression was assessed by immunohistochemical examination of embryo sections. Both alpha 5 and beta 1 subunit mRNAs were expressed throughout the stages examined. Expression of both subunit proteins was found in the endoderm at Day 14 but not at Day 18 or later. Fibronectin reactivity was not present at any of the stages examined. Between Days 18 and 21, beta 1-reactivity appeared on the lateral surfaces of the trophoblast cells. Day 24 trophoblast binucleate cells showed intense staining with the beta 1 antibody, suggesting that a beta 1-integrin is involved in binucleate cell migration.
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PMID:Fibronectin receptors in preimplantation development: cloning, expression, and localization of the alpha 5 and beta 1 integrin subunits in bovine trophoblast. 754 39

1. Kallikrein enzyme activity has been previously reported in the uterus of several species and implicated in implantation and parturition. In order to provide further evidence for a local kallikrein-kinin system in this tissue, we wished to determine if the gene encoding kallikrein (KLK1) was expressed in the human uterus and determine the pattern of its expression across the menstrual cycle. 2. Reverse-transcriptase polymerase chain reaction (RT-PCR) of endometrial and myometrial total RNA coupled with Southern blot analysis showed that KLK1 was expressed in the human endometrium and myometrium. Endometrial expression of KLK1 was confirmed by DNA sequence analysis of the PCR products. Kallikrein was also localized by immunocytochemistry, primarily in the glandular epithelium of the endometrium. 3. Quantitative RT-PCR of 37 endometrial samples ranging from day 1 to 29 from across the menstrual cycle showed significantly higher KLK1 (kallikrein) expression from the mid proliferative to the early secretory phase compared with the late secretory and menstrual phases. 4. We have demonstrated for the first time that KLK1, the gene encoding glandular kallikrein, is expressed in the human uterus. The increase in endometrial KLK1 gene expression during the proliferative phase of the menstrual cycle suggests a role for kallikrein in the preparation of the endometrial lining for implantation.
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PMID:Glandular kallikrein gene expression in the human uterus. 774 74

A cDNA coding for a new human matrix metalloproteinase (MMP) has been cloned from a cDNA library derived from a breast tumor. The isolated cDNA contains an open reading frame coding for a polypeptide of 471 amino acids. The predicted protein sequence displays extensive similarity to the previously known MMPs and presents all the structural features characteristic of the members of this protein family, including the well conserved PRCGXPD motif, involved in the latency of the enzyme and the zinc-binding domain (HEXGHXXXXXHS). In addition, this novel human MMP contains in its amino acid sequence several residues specific to the collagenase subfamily (Tyr-214, Asp-235, and Gly-237) and lacks the 9-residue insertion present in the stromelysins. According to these structural characteristics, the MMP described herein has been tentatively called collagenase-3, since it represents the third member of this subfamily, composed at present of fibroblast and neutrophil collagenases. The collagenase-3 cDNA was expressed in a vaccinia virus system, and the recombinant protein was able to degrade fibrillar collagens, providing support to the hypothesis that the isolated cDNA codes for an authentic collagenase. Northern blot analysis of RNA from normal and pathological tissues demonstrated the existence in breast tumors of three different mRNA species, which seem to be the result of the utilization of different polyadenylation sites present in the 3'-noncoding region of the gene. By contrast, no collagenase-3 mRNA was detected either by Northern blot or RNA polymerase chain reaction analysis with RNA from other human tissues, including normal breast, mammary fibroadenomas, liver, placenta, ovary, uterus, prostate, and parotid gland. On the basis of the increased expression of collagenase-3 in breast carcinomas and the absence of detectable expression in normal tissues, a possible role for this metalloproteinase in the tumoral process is proposed.
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PMID:Molecular cloning and expression of collagenase-3, a novel human matrix metalloproteinase produced by breast carcinomas. 820


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