A variant of DNA polymerase beta is not cancer specific.
DNA polymerase beta (pol beta) carries out base-excision repair (BER) required for DNA maintenance, replication, and recombination in eukaryotic cells. A variant characterized by a deletion of exon 11, an 87-bp region in the catalytic domain (pol betadelta208-236), was previously described as a possible cause of genomic instability in cancer. The variant form was hypothesized to act in a dominant negative fashion, due to the fact that the variant inhibits the gap filling and DNA binding activities of the wild-type pol beta protein. DNA polymerase beta transcripts were analyzed in 8 breast cancer cell lines, snap-frozen benign breast tissues from 10 women, and lymphocytes from 10 normal controls, using reverse-transcription polymerase chain reaction (RT-PCR) and three separate primer pairs. The exon 10-12 splice site (variant) was identified using a primer designed to span the spliced exons and by sequencing RT-PCR products that included exon 10, exon 11 (if present), and exon 12. In all of the samples tested, we found both the wild-type and exon 11 87-bp deleted variant mRNAs expressed. We conclude that expression of the DNA polymerase beta variant (pol betadelta208-236) is ubiquitous and not breast cancer specific.
Bu
Dawei
D
Department of Surgery, UT Southwestern Medical Center, Dallas, Texas 75390-9155, USA.
Cler
Leslie R
LR
Lewis
Cheryl M
CM
Euhus
David M
DM
D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics*; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000201:enzymology / Q000235:genetics; D019951:DNA Polymerase beta / Q000235:genetics*; D017931:DNA Primers; D004261:DNA Replication; D005091:Exons; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D013736:Testicular Neoplasms / Q000201:enzymology / Q000235:genetics
D017931:DNA Primers; D019951:DNA Polymerase beta