Lack of mutations in DNA polymerase beta of estradiol-induced hamster kidney tumors: sequence of hamster DNA polymerase beta cDNA

We examined the effects of estradiol (E-2), the natural estrogenic hormone, on the structure and expression of DNA polymerase beta (DNA pol beta), a D NA repair gene, from E-2-induced primary kidney tumors of twelve Syrian ham sters, their metastases, and from kidney tissues surrounding the tumors. We sequenced the coding region of the hamster DNA pol beta and found it to di ffer from that of the human by 11%. No mutations were detected in the entir e coding region including the catalytic domain of the DNA pol beta from E-2 --- induced primary kidney tumors, their metastases, or from kidney tissues surrounding the tumors. The expression of the DNA pol beta mRNA was also n ot significantly altered in E-2-induced kidney tumors or in kidney tissues surrounding the tumors compared to that of control kidney tissues. These re sults suggest that mutations in the DNA pol beta gene may not be involved i n the induction or malignant progression of hamster kidney tumors induced b y E-2. The nucleotide sequence of the hamster DNA pol beta described here w ill be useful for the study of the structure and expression of this gene.