Uterus hyperplasia and increased carcinogen-induced tumorigenesis in mice carrying a targeted mutation of the Chk2 phosphorylation site in Brca1 |
| |
| Authors: | Kim Sang Soo Cao Liu Li Cuiling Xu Xiaoling Huber L Julie Chodosh Lewis A Deng Chu-Xia |
| |
| Affiliation: | Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Dr., Bethesda, MD 20892, USA. |
| |
| Abstract: | The tumor suppressor BRCA1 contains multiple functional domains that interact with many proteins. After DNA damage, BRCA1 is phosphorylated by CHK2 at serine 988, followed by a change in its intracellular location. To study the functions of CHK2-dependent phosphorylation of BRCA1, we generated a mouse model carrying the mutation S971A (S971 in mouse Brca1 corresponds to S988 in human BRCA1) by gene targeting. Brca1(S971A/S971A) mice were born at the expected ratio without a developmental defect, unlike previously reported Brca1 mutant mice. However, Brca1(S971A/S971A) mice suffered a moderately increased risk of spontaneous tumor formation, with a majority of females developing uterus hyperplasia and ovarian abnormalities by 2 years of age. After treatment with DNA-damaging agents, Brca1(S971A/S971A) mice exhibited several abnormalities, including increased body weight, abnormal hair growth pattern, lymphoma, mammary tumors, and endometrial tumors. In addition, the onset of tumor formation became accelerated, and 80% of the mutant mice had developed tumors by 1 year of age. We demonstrated that the Brca1(S971A/S971A) cells displayed reduced ability to activate the G(2)/M cell cycle checkpoint upon gamma-irradiation and to stabilize p53 following N-methyl-N'-nitro-N-nitrosoguanidine treatment. These observations suggest that Chk2 phosphorylation of S971 is involved in Brca1 function in modulating the DNA damage response and repressing tumor formation. |
| |
| Keywords: | |
| 本文献已被 PubMed 等数据库收录！ |
|
