Regulation of DNA metabolic enzymes upon induction of preB cell development and V(D)J recombination: up-regulation of DNA polymerase delta.
Withdrawal of interleukin-7 from cultured murine preB lymphocytes induces cell differentiation including V(D)J immunoglobulin gene rearrangements and cell cycle arrest. Advanced steps of the V(D)J recombination reaction involve processing of coding ends by several largely unidentified DNA metabolic enzymes. We have analyzed expression and activity of DNA polymerases alpha, beta, delta and epsilon, proliferating cell nuclear antigen (PCNA), topoisomerases I and II, terminal deoxynucleotidyl transferase (TdT) and DNA ligases I, III and IV upon induction of preB cell differentiation. Despite the immediate arrest of cell proliferation, DNA polymerase delta protein levels remained unchanged for approximately 2 days and its activity was up-regulated several-fold, while PCNA was continuously present. Activity of DNA polymerases alpha,beta and epsilon decreased. Expression and activity of DNA ligase I were drastically reduced, while those of DNA ligases III and IV remained virtually constant. No changes in DNA topoisomerases I or II expression and activity occurred and TdT expression was moderately increased early after induction. Our results render DNA polymerase delta a likely candidate acting in DNA synthesis related to V(D)J recombination in lymphocytes.
Jessberger
R
R
Basel Institute for Immunology, Grenzacherstrasse 487, CH-4005 Basel, Switzerland. jessberger@bii.ch
Schär
P
P
Robins
P
P
Ferrari
E
E
Riwar
B
B
Hübscher
U
U
D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D011088:DNA Ligases / Q000235:genetics / Q000378:metabolism; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism; D004254:DNA Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D004258:DNA Polymerase III; D004264:DNA Topoisomerases, Type I / Q000235:genetics / Q000378:metabolism; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D015151:Immunoblotting; D015851:Interleukin-7 / Q000494:pharmacology; D008214:Lymphocytes / Q000378:metabolism*; D051379:Mice; D011233:Precipitin Tests; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology*; D045567:VDJ Recombinases
D015851:Interleukin-7; D018809:Proliferating Cell Nuclear Antigen; D004254:DNA Nucleotidyltransferases; D045567:VDJ Recombinases; D004253:DNA Nucleotidylexotransferase; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase; D004264:DNA Topoisomerases, Type I; D004250:DNA Topoisomerases, Type II; D011088:DNA Ligases