The role of the BRCA1 and BRCA2 gene in the pathogenesis of breast cancer

分子病理学的研究集中在定义基因的变化，这些基因是常见疾病(如癌症和出生缺陷)遗传易感性的基础。目前正在研究的是遗传性乳腺癌和卵巢癌基因BRCA1和BRCA2。这些蛋白质的生物学功能目前尚不清楚。此前，我们发现了哪些蛋白质与BRCA1特异相互作用。我们还发现BRCA1对控制其他基因的表达很重要，并且在DNA修复中发挥作用。最近的实验表明，BRCA1似乎有助于识别和消除可能形成肿瘤的细胞。我们现在知道，乳腺癌、卵巢癌和前列腺癌风险的增加与这些基因的遗传变异有关，是因为这些突变的蛋白质无法在DNA修复途径中发挥作用。我们使用酵母细胞作为实验模型来测试在人类中发现的突变的功能后果。我们还开发了一种系统，用于识别与BRCA1相互作用的蛋白质。 众所周知，BRCA1的作用是将蛋白质泛素转移到其他蛋白质上。通过这一动作，BRCA1可能传递了启动DNA修复过程的信号。发生这种转移的蛋白质的身份尚不清楚。我们计划鉴定这些靶蛋白。我们开发了两个能够测量BRCA1活性的系统。这些系统现在被用来识别与乳腺肿瘤形成有关的特定蛋白质。在过去的一年里，我们一直在进行使用标记泛素表达结构的实验。这些实验取得了成功，因为我们能够跟踪泛素转移到目标蛋白质的命运。到目前为止，还没有鉴定出BRCA1BARD1特异性底物。我们对BARD1BRCA1组分进行了亚细胞分离浓缩。这些实验未能丰富泛素化的蛋白质。 在过去，我们应用生物信息学的方法来探索基因组结构在蛋白质进化中可能扮演的角色。对BRCA1和BRCA2基因的研究使我们发现了一种特定类型的基因结构与进化变化率之间的新联系。这一观察结果似乎适用于几乎任何基因，并适用于所有后生动物的谱系。我们最近完成了对六个基因组中每个外显子的研究。我们在较小样本中观察到的规则在这个较大的集合中得到了证实。

Research in the Molecular Pathogenesis is focused on defining changes in the genes that underlie inherited susceptibilities to common diseases such as cancer and birth defects. Currently under investigation are the inherited breast and ovarian cancer genes, BRCA1 and BRCA2. The biological function of these proteins is currently unknown. Previously, we discovered which proteins specifically interact with BRCA1. We also have found that BRCA1 is important for controlling the expression of other genes and is plays a role in DNA repair. Recent experiments has revealed that BRCA1 appears to help in the process of recognizing and eliminating cells that may progress to form tumors. We now know that the increase in breast, ovarian and prostate cancer risk associated with genetic variants in these genes is due to a failure of these mutated proteins to function in the DNA repair pathway. We used yeast cells as an experimental model to test the functional consequences of mutations found in humans. We have also developed a system for identifying proteins that interact with BRCA1. It is also known that BRCA1 acts to transfer the protein ubiquitin onto other proteins. Through this action BRCA1 may be transferring a signal to start the DNA repair process. The identity of the protein to which this transfer occurs is unknown. We plan to identify these target proteins. We developed two systems capable of measuring this activity of BRCA1. These systems are now being used to identify specific proteins involved in breast tumor formation. During the past year we have been carrying out experiments using tagged ubiquitin expression constructs. These experiments have been successful in that we are able to follow the fate of the ubiquitin as it transferred to target proteins. To date, no BRCA1BARD1 speciific substrates have been identified. We have carried out subcellular fractionation enrich for BARD1BRCA1 fractions. These experiments have failed to enrich for ubiquitinated proteins. In the past we applied a bioinformatics approach to probe the role that genomic structure may play in protein evolution. The study of the BRCA1 and BRCA2 genes has led us to discover a new connection between a specific type of gene structure and evolutionary rates of changes. This observation appears to be generalizable to almost any gene and holds true across all metazoan lineages. We recently completed the study of all the exons in each of six genomes. The rules we observed for our smaller sample have been confirmed in this larger set.