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)

Thymidine kinase and DNA polymerase enzyme activities were measured in epididymal adipose tissue from rats of 12 to 182 days of age. Both enzymes showed highest specific activity during the suckling period; by 35 days of age both thymidine kinase and DNA polymerase enzyme activities had decreased to stable lower levels. The activities of the two proliferative enzymes resembled the pattern of [3H]thymidine incorporation into preadipocytes shown by Greenwood and Hirsch (1) and the data support the concept that a pool of preadipocytes develops during the first 4 to 5 weeks postnatally. Further, the thymidine kinase and DNA polymerase enzyme activities were correlated with the rate of DNA accretion in the preadipocyte fraction of the tissue. Since thymidine kinase activity can be measured in 20 to 40 mg of tissue. Since thymidine kinase activity can be measured in 20 to 40 mg of tissue, the technique can be adapted for measurement of enzyme levels in human or animal biopsy samples when radio-isotope studies are not advisable or only small quantities of tissue are available.
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PMID:Thymidine kinase and DNA polymerase activity during postnatal growth of the epididymal fat pad. 43 Feb 14

In the epididymis of young rats, activities of DNA polymerases alpha, beta and gamma and DNA topoisomerase I decreased after castration. DNA polymerase alpha and gamma increased with androgen administration and activity reached 81.3% and 78.0%, respectively, of the activity in the sham-operated group on day 21. Activity of DNA polymerase beta remained at the activity of day 7 during androgen administration and was almost the same as that in the sham-operated group on day 21. DNA topoisomerase I activity showed a slight increase with androgen administration and reached 50.3% of that in the sham-operated group. The activities of these enzymes were not fully restored to those in the sham-operated group. These results indicate that in young rats activities of epididymal DNA polymerase alpha and gamma and DNA topoisomerase I are partially, and that of DNA polymerase beta wholly, dependent on androgens and may provide a means of investigating the regulation of epididymal cell proliferation.
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PMID:Androgenic regulation of enzymes involved in DNA synthesis in epididymis of young rats. 133 37

The sperm-free fluid fraction of epididymal semen obtained from males of four mouse strains contained a DNA polymerase activity with properties of murine retrovirus reverse transcriptase (RT). Epididymal fluids from two of the strains of mice, NIH Swiss and New Zealand Black (NZB), had an order of magnitude more enzyme activity per microgram of protein than did the fluids of C57Bl/6 and Balb/c males. Most of the enzyme activity in the Swiss and NZB males, but not in the C57Bl/6 and Balb/c males, banded in isopycnic sucrose gradients at the buoyant density of retrovirus particles. The males were fertile and free of tumor or other detectable disease up to 17 months of age. The evidence suggests RT activity is ubiquitous in the male reproductive tract of mice and may or may not be associated with virus particles.
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PMID:Evidence that reverse transcriptase is a component of murine epididymal fluid. 620 68

Chromatin of rat elongating spermatids, steps 12-13, is distinguished by the replacement of histones with transition proteins and the presence of nicks within its DNA which are formed by an endogenous nuclease, possibly DNA topoisomerase II (topo II). Using an affinity-purified anti-topo II antibody, protein bands of approximately 161 and approximately 137 kDa were detected on immunoblots of pachytene spermatocytes and elongating spermatids, respectively. In cryosections, topo II was localized to meiotic chromosomes of pachytene spermatocytes and to nuclei of elongating spermatids. Extracts of isolated testicular nuclei and sonication-resistant spermatid nuclei (steps 12-19) demonstrated topo II activity as determined by the decatenation of kinetoplast DNA. The potential relationship between nucleoprotein changes during spermatogenesis and the formation of nicks was also examined. Heterogeneous testicular and sonication-resistant spermatid nuclei were treated with 0.8 mM protamine, followed by nick translation in the absence of DNase I. In both cases, there was a dramatic decrease in DNA polymerase I-dependent label incorporation. To determine whether or not endogenous nicks were present in mature sperm, but were inaccessible due to protamine-DNA interactions, epididymal sperm were extracted with high salt-dithiothreitol, followed by nick translation in the absence or presence of DNase I. Extracted sperm nuclei did not nick translate in the absence of DNase I; however, incorporation increased with increasing concentrations of DNase I, indicating that endogenous nicks were repaired prior to the completion of spermatogenesis. These and previously published results suggest that topo II in elongating spermatids may be involved in the DNA alterations that take place during spermatogenesis, including changes in DNA topography, repair, and loop formation, and may serve as a component of the nuclear matrix. The temporal appearance and disappearance of endogenous nicks may reflect the changes that elongating spermatid DNA undergoes as a consequence of alterations in nucleoprotein composition to establish the condensed state of the mature spermatozoon.
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PMID:Nicking of rat spermatid and spermatozoa DNA: possible involvement of DNA topoisomerase II. 839 68