title: Murine terminal deoxynucleotidyl transferase: cellular distribution and response to cortisone.
abstract: The mouse thymus contains two forms of terminal deoxynucleotidyl transferase (TdT) which are distinguishable by the salt concentration necessary to elute them from a phosphocellulose column, by their distrubtion among the thymocyte subpopulations, and by their sensitivity to cortisone treatment. In the whole thymus the later eluting peak (peak II) is the predominant one with about 3-10% of the total activity appearing in peak I. Both peak I and peak II activities are most sensitively assayed by the polymerization of dGMP onto an oligo(dA) primer. The minor population of thymocytes which is less dense and cortisone-resistant contains a higher specific activity of peak I TdT. The majority of TdT activity is, however, found in the major population of thymocytes which occurs in the center region of a bovine serum albumin gradient and is cortisone-sensitive. A very low level of an activity indistinguishable from peak II TdT activity is also detected in the mouse bone marrow. Other tissues, such as spleen, liver, heart, and brain lack detectable amounts of TdT activity.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000201:enzymology; D001854:Bone Marrow Cells; D001921:Brain / Q000201:enzymology; D002384:Catalysis; D002458:Cell Fractionation; D002482:Cellulose; D002499:Centrifugation, Density Gradient; D002845:Chromatography; D003348:Cortisone / Q000494:pharmacology*; D003597:Cytosine Nucleotides; D004254:DNA Nucleotidyltransferases / Q000032:analysis*; D003864:Depression, Chemical; D008099:Liver / Q000201:enzymology; D008198:Lymph Nodes / Q000201:enzymology; D051379:Mice; D008815:Mice, Inbred Strains; D009206:Myocardium / Q000201:enzymology; D010758:Phosphorus; D012710:Serum Albumin, Bovine; D013154:Spleen / Q000201:enzymology; D013942:Thymine Nucleotides; D013950:Thymus Gland / Q000201:enzymology*
chemical_list: D003597:Cytosine Nucleotides; D013942:Thymine Nucleotides; D012710:Serum Albumin, Bovine; D010758:Phosphorus; D002482:Cellulose; D004254:DNA Nucleotidyltransferases; D003348:Cortisone