hMYH cell cycle-dependent expression, subcellular localization and association with replication foci: evidence suggesting replication-coupled repair of adenine:8-oxoguanine mispairs.
The human MutY homolog, hMYH, is an adenine-specific DNA glycosylase that removes adenines or 2-hydroxyadenines mispaired with guanines or 8-oxoguanines. In order to prevent mutations, this activity must be directed to the newly synthesized strand and not the template strand during DNA synthesis. The subcellular localization and expression of hMYH has been studied in serum-stimulated, proliferating MRC5 cells. Using specific antibodies, we demonstrate that endogenous hMYH protein localized both to nuclei and mitochondria. hMYH in the nuclei is distinctly distributed and co-localized with BrdU at replication foci and with proliferating cell nuclear antigen (PCNA). The levels of hMYH in the nucleus increased 3- to 4-fold during progression of the cell cycle and reached maximum levels in S phase compared to early G(1). Similar results were obtained for PCNA, while there were no notable changes in expression of 8-oxoguanine glycosylase or the human MutT homolog, MTH1, throughout the cell cycle. The cell cycle-dependent expression and localization of hMYH at sites of DNA replication suggest a role for this glycosylase in immediate post-replication DNA base excision repair.
Boldogh
I
I
Department of Microbiology, Sealy Center for Environmental Health and Medicine, University of Texas Medical Branch, Galveston, TX 77555-1071 USA.
Milligan
D
D
Lee
M S
MS
Bassett
H
H
Lloyd
R S
RS
McCullough
A K
AK
D000225:Adenine / Q000378:metabolism*; D020137:Base Pair Mismatch / Q000235:genetics*; D015153:Blotting, Western; D002453:Cell Cycle; D002455:Cell Division; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology / Q000378:metabolism; D003593:Cytoplasm / Q000201:enzymology / Q000378:metabolism; D045647:DNA Glycosylases; D004260:DNA Repair / Q000235:genetics*; D045643:DNA Repair Enzymes; D004261:DNA Replication; D043382:DNA-Formamidopyrimidine Glycosylase; D019084:Fluorescent Antibody Technique, Indirect; D016193:G1 Phase; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism*; D006801:Humans; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D021381:Protein Transport; D016196:S Phase; D014407:Tumor Cells, Cultured
D018809:Proliferating Cell Nuclear Antigen; C024829:8-hydroxyguanine; D006147:Guanine; D010744:Phosphoric Monoester Hydrolases; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; C061738:mutY adenine glycosylase; D043382:DNA-Formamidopyrimidine Glycosylase; C078207:8-oxodGTPase; D045643:DNA Repair Enzymes; D000225:Adenine