Brca1 in development and tumorigenesis

Brca1 的发育和肿瘤发生

• 批准号: 8553546
• 负责人: Chuxia Deng
• 金额: $ 72.25万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8553546
• 关键词: Affect; Age-Years; Aging; Alternative Splicing; Amino Acids; Animals; Apoptosis; Biological Process; Breast; Breast Cancer Model; Cancer Etiology; Cell Cycle Progression; Cells; Centrosome; Cyclin A; Cyclin E; DNA Repair; Defect; Development; Duct (organ) structure; Embryo; Epithelial; Exhibits; Exons; Female; Fibroblasts; Genes; Germ-Line Mutation; Hereditary Breast Carcinoma; Human; Hyperplasia; Knock-in Mouse; Length; Lobular; Malignant neoplasm of ovary; Mammary gland; Modeling; Mus; Mutant Strains Mice; Mutation; Physiological; Play; Point Mutation; Population; Protein Isoforms; Proteins; RNA Splicing; Reporting; Second Primary Cancers; Series; Slice; Transcriptional Regulation; Variant; Woman; malignant breast neoplasm; mortality; mouse model; mutant; null mutation; prevent; tumor; tumorigenesis

In the past year, we generated and analyzed a mouse model carrying a mutation that blocks the slicing between BRCA1 exons 10 and 11. Alternative splicing in the BRCA1 locus generates multiple protein products including BRCA1-Delta11, which is identical to the BRCA1 full-length isoform (BRCA1-FL) except for the absence of exon 11. To understand the physiologic functions of BRCA1-Delta11, we used a knock-in approach that blocks alternative splicing between exons 10 and 12 to prevent the formation of this form of BRCA1. We showed that homozygous mutant mice (Brca1(FL/FL)) were born at a Mendelian ratio without obvious developmental defects. However, the majority of Brca1(FL/FL) female mice showed mammary gland abnormalities and uterine hyperplasia after one year of age with spontaneous tumor formation. Cultured Brca1(FL/FL) cells exhibited abnormal centrosome amplification and reduction of G(1) population that was accompanied by accumulation of cyclin E and cyclin A. Accumulation of cyclin E was also found in epithelial layers of dilated ducts and hyperproliferative lobular regions in the mammary glands of Brca1(FL/FL) mice. These observations provide evidence that BRCA1 splicing variants are involved in BRCA1 functions in modulating G(1)/S transition, centrosome duplication, and repressing tumor formation. Thus, together with mutant mice generated earlier, we have generated and reported a total of five mutant models for BRCA1, including two null mutations, one conditional mutation, two isoform mutations and one point mutation. Our studies using these models demonstrate that BRCA1 plays essential functions in many biological processes, including transcription regulation, cell cycle progression, apoptosis, DNA damage repair, centrosome duplication and animal aging.

在过去的一年中，我们生成和分析了一种携带一个突变的鼠标模型，该突变阻塞了BRCA1外显子10和11之间的切片。BRCA1基因座中的替代剪接生成了多种蛋白质产品，包括BRCA1-DELTA11，该产品与BRCA1全长同工型（BRCA1-FL）相同，除了理解Exon 11的缺失外，该剪接均与BRCA1全长同工型（BRCA1-FL）相同。敲入方法可以阻止外显子10和12之间的替代剪接，以防止这种形式的BRCA1形成。我们表明，纯合突变小鼠（BRCA1（FL/FL））以孟德尔的比率出生而没有明显的发育缺陷。然而，大多数BRCA1（FL/FL）雌性小鼠表现出乳腺异常，并在自发肿瘤形成后一岁后发生子宫增生。培养的BRCA1（FL/FL）细胞表现出异常的中心体扩增和G（1）种群的减少，伴随着细胞周期蛋白E和细胞周期蛋白A的积累。在扩张的导管的上皮层中也发现了细胞周期蛋白E的积累。这些观察结果提供了证据，表明BRCA1剪接变体参与了BRCA1功能调节G（1）/s转变，中心体重复和抑制肿瘤形成。因此，与先前产生的突变小鼠一起，我们已经生成并报告了五个BRCA1突变模型，包括两个无效突变，一个条件突变，两个同工型突变和一个点突变。我们使用这些模型的研究表明，BRCA1在许多生物学过程中起着重要的功能，包括转录调控，细胞周期进展，凋亡，DNA损伤修复，中心体重复和动物衰老。