Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.7 (DNA polymerase)
17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The production of mouse mammary tumor virus (MMTV) in primary cell cultures of BALB/cfC3H mammary tumor cells was measured by radioimmune assay and RNA=dependent DNA polymerase activity. Maximum virus production was dependent on cell density, nutritional milieu, and hormone supplementation. The addition of insulin (u), estradiol-17 beta (E2), progesterone (P), prolactin (PRL), or thyroxine (T3) alone had little or no effect on MMTV production. Hydrocortisone (F) had a primary stimulatory effect. The combination of I, F, and T3 increased MMTV levels. The combinations containing I, F, and E2 had the greatest stimulatory effect. The stimulation of MMTV production was dose dependent. These experiments demonstrate that a variety of hormones act in a synergistic manner to stimulate MMTV production.
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PMID:Hormone synergism in the in vitro production of the mouse mammary tumor virus. 18 27

We investigated the relationship between prolactin content and DNA replication in the anterior pituitary gland. Thymidine incorporation in pregnant rats is significantly lower than in virgin controls. This is accompanied by a decreased activity of DNA polymerase. Sulpiride administration to pregnant rats enhances thymidine incorporation to levels similar to virgin controls. The results indicate a negative feedback between prolactin content and DNA synthesis in the rat anterior pituitary gland.
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PMID:Cell proliferation in the rat pituitary gland: a mechanism of control in prolactin cells. 44 82

During development of the rat anterior pituitary gland (APG) there is a fall in DNA replication which is accompanied by a decline in the activity of the soluble DNA polymerase and of an endonuclease. This latter enzyme is capable of activating the DNA template for the DNA polymerase assay. Sulpiride sulfate, a drug known to produce prolactin release from the APG, increases thymidine incorporation in the APG 20 h after the injection. This drug also enhances the activity of the soluble DNA polymerase while that of the endonuclease and thymidine kinase does not change. The results suggest that the intracellular prolactin content regulates DNA replication in mammotrophs and that the soluble DNA polymerase plays an important role in this regulation.
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PMID:DNA synthesis in the pituitary gland of the rat. Effect of sulpiride and postnatal maturation. 47 Nov 96

The entire 2nd thoracic mammary gland of the immature virgin BALB/c mouse was stimulated to full lobulo-alveolar (LA) growth after 120 h organ culture in hormone supplemented medium. The minimal hormonal combination required was insulin (I) + prolactin (Prl) + aldosterone (A). The corticosteroid was replaceable by oestradiol-17beta (E) + progesterone (P). The combination I alone or I + the steroid hormone(s) failed to induce the LA development and similar results were also evident in presence of Prl + the steroids. Incubation of the glands in medium with I + Prl + A activated a sequential rise of RNA, protein and DNA synthesis. A near maximal increase of RNA synthesis was present at 48 h in the medium with I + Prl, addition of the steroid hormones did not show further stimulatory effect. Supplementation of the medium with I + Prl and the adrenal or the ovarian steroids was needed for maximal activation of protein synthesis at 72 h and DNA replication at 96 h. The medium with I alone did not show a substantial rise of macromolecular biosynthesis in the mammary gland in organ culture. The highest level of DNA polymerase activity was observed at 72 h in glands cultivated in medium with I + Prl and A or E + P. Only a modest increase of DNA polymerase activity was present in glands cultivated with I alone or I + Prl. Prior treatment of the glands (cultivated with I + Prl + A) with actinomycin D or puromycin resulted into 44 and 40% reduction of DNA polymerase activity suggesting hormone-induced synthesis of the enzyme before the rise of DNA synthesis in the mammary cells at 96 h in organ culture. Significance of these results with respect to the action of the "growth-promoting" hormones in the mammary gland in organ culture and in the animal has been discussed.
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PMID:Action of growth-promoting hormones on macromolecular biosynthesis during lobulo-alveolar development of the entire mammary gland in organ culture. 124 65

The growth potential of 65 pituitary adenomas was determined by histochemical analysis with Ki-67 and anti-DNA polymerase alpha monoclonal antibodies, bromodeoxyuridine (BrdUdR) labeling, and counts of argyrophilic nucleolar organizer regions (Ag-NORs). The mean proliferating cell indices (PCIs) determined by Ki-67 and anti-DNA polymerase alpha and the BrdUdR labeling index (LI) were generally very low [1.0 +/- 0.2%, 1.1 +/- 0.2%, and 0.5 +/- 0.1% (+/- SE), respectively]. Apart from adrenocorticotropic hormone-positive adenomas, which had significantly higher indices, there were no statistically significant differences in the indices among the other subtypes of pituitary adenomas. Recurrent tumors had higher Ki-67 and DNA polymerase alpha PCIs and BrdUdR LIs (3.6%, 4.2%, 1.4%) than primary tumors (0.8%, 0.8%, 0.3%; P less than 0.005). The number of Ag-NORs did not correlate significantly with any of the three indices. The mean number of Ag-NORs was higher in nonfunctioning adenomas than in functioning adenomas (2.04 vs 1.66, P less than 0.005); among prolactin-positive adenomas, those treated preoperatively with bromocriptine had more Ag-NORs than untreated tumors (1.75 vs 1.57, P less than 0.005). These results suggest that the Ki-67 and DNA polymerase alpha PCIs and the BrdUdR LI predict the growth potential of individual pituitary adenomas, whereas the number of Ag-NORs appears to correlate with hormone production rather than with the proliferative potential.
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PMID:Histochemical study of pituitary adenomas with Ki-67 and anti-DNA polymerase alpha monoclonal antibodies, bromodeoxyuridine labeling, and nucleolar organizer region counts. 138 60

A GH cDNA was specifically amplified from cDNAs constructed from total RNA of bullfrog (Rana catesbeiana) adenohypophyses employing the DNA polymerase chain reaction. Sequencing analysis revealed that the cDNA clone thus obtained was 654 bp in length, and included an open reading frame encoding the entire sequence of mature GH, with its signal peptide. Slight discrepancies were noted between the deduced amino acid sequence and that determined by direct protein sequencing of purified bullfrog GH or that deduced from the nucleotide sequence reported previously. The length of the bullfrog GH mRNA was estimated to be about 1.2 kb by Northern blot analysis. Homologies of nucleotide and amino acid sequences between GH and prolactin of bullfrog origin were 48% and 26% respectively. Using the cDNA as a probe, the content of GH mRNA in the pituitary of larval and adult bullfrogs was measured. GH mRNA levels were relatively low at the preclimax stage, and rose markedly during climax. In juvenile frogs, GH mRNA levels in the pituitary were extremely high and declined towards adulthood. This finding suggests that the increase in plasma and pituitary GH levels reported previously accompanies the increase in GH synthesis.
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PMID:Cloning of a bullfrog growth hormone cDNA: expression of growth hormone mRNA in larval and adult bullfrog pituitaries. 147 15

Total mRNA isolated from bovine pituitary was used as a template to synthesize double-stranded cDNA with reverse transcriptase and E. coli DNA polymerase. Recombination was performed using pBR322 as the cloning vector and the oligo dG-tailed and oligo dC-tailed method. The recombinant plasmid was then introduced into E. coli to construct the cDNA library of bovine pituitary mRNA. The labelled synthetic bovine prolactin (bPrl) gene fragment was used as hybridization probe to screen the positive clones, which were then subjected to enzymatic mapping and DNA sequence analysis. The results demonstrate that the positive clones contain a full length bPrl cDNA sequence. The clones obtained were subsequently trimmed, linked to a tac promoter, introduced into E. coli JM103, and expressed under the induction of IPTG. The SDS-PAGE indicates the existence of expression product, and the result of ELISA shows that the product has the same immune activity as native bPrl.
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PMID:Cloning and expression of bovine prolactin cDNA in Escherichia coli. 213 25

Blast cells in acute leukemia and lymphoma appear to be "frozen" at various stages of lymphoid cell differentiation. The enzymatic and antigenic phenotypes expressed by these cells often correspond to the gene products of their normal precursors. We have used various immunocytochemical and enzymatic techniques to identify membrane, nuclear, and cytoplasmic markers associated with the prolactin-dependent Nb2 lymphoma cell line. The Nb2 cells, whether stationary or in log-phase growth, did not express any surface immunoglobulin. However, 100% of the Nb2 cells bound both a monoclonal antibody raised to rat thymocyte W3/25-HLK, which specifically binds an antigenic determinant on rat T-helper cells, and second monoclonal antibody OX8-HL, which identifies rat nonhelper T-cells. Transmission electron microscopy showed no evidence of phagocytic vacuoles, and activity of the lysosomal enzyme muramidase was also absent. There was no evidence of the DNA polymerase enzyme terminal deoxynucleotidyl transferase. alpha-Naphthyl acetate esterase activity was indicated in about 50% of the Nb2 cells by a faint particulate cytoplasmic staining similar to that found in thymocytes. Rosette formation with guinea pig erythrocytes, a property of mature rat thymocytes, was not observed with Nb2 cells. The data suggest that the Nb2 tumor may have arisen from a thymocyte at an intermediate stage of differentiation. The presence of Thy-like alpha-naphthyl acetate esterase pattern and the binding of both W3/25-HLK and OX8-HL support the thymic origin and relative immaturity of these lymphoid cells. It is becoming increasingly apparent that a significant proportion of lymphomas and leukemias also originate in undifferentiated thymic cels.
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PMID:Thymic origin of the prolactin-dependent Nb2 lymphoma cell line. 704 17

The administration of haloperidol increased serum prolactin and decreased the pituitary concentration of prolactin 15 min after its administration. Concomitantly there was a stimulation in the synthesis of DNA and the activity of DNA polymerase alpha in the anterior pituitary gland that was greater in oestrogenized than in non-oestrogenized male rats. Both these effects were greatly reduced by clomiphene in the oestrogenized male rats, although it did not affect the release of prolactin produced by haloperidol. In non-oestrogenized animals clomiphene abolished the stimulatory effect of haloperidol on the synthesis of DNA. These results suggest that the reduction in the intracellular levels of prolactin are a primary event in the oestrogen mediated stimulation of cell proliferation by prolactin releasing agents.
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PMID:Effect of haloperidol on the synthesis of DNA in the pituitary gland of the rat. 706 7

Changes in the activity of DNA polymerase and [3H]thymidine incorporation into the DNA of the anterior pituitary gland were studied in oestrogenized male and pregnant rats. The activities of DNA polymerases alpha and beta, extracted in Tris--HCl or in sodium phosphate buffer were characterized according to their optimum pH and sensitivity to N-ethyl-maleimide. In the Tris-soluble fraction DNA polymerase activity is almost exclusively alpha, while in the phosphate soluble fraction it is a mixture of alpha and beta. The administration of oestrogens to male rats increases [3H]thymidine incorporation and enhances the activity of DNA polymerases in the Tris-soluble fraction, while the activity of the phosphate-soluble enzyme does not change. Sulpiride administration results in a further increment of [3H]thymidine incorporation and of DNA polymerase activity in the Tris-soluble fraction. In pregnant rats sulpiride also produces an increment of DNA polymerase activity only in the Tris-soluble fraction. Thus, the activity of the Tris-soluble fraction from APG behaves as DNA polymerase alpha. This activity changes in parallel with [3H]thymidine incorporation into DNA which is an indication of cell proliferation in the gland. This is discussed with respect to a negative feedback mechanism between intracellular prolactin concentration and DNA synthesis in the APG.
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PMID:DNA polymerases in the rat pituitary gland. Effect of oestrogens and sulpiride. 739 1


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