The Molecular Genetics of MUC16

CA125抗原是卵巢上皮性癌的特异性血清标志物，临床上用于监测治疗反应和复发情况。最近对编码CA125抗原核心肽的cDNA分子的鉴定和克隆表明，它与一个膜相关粘蛋白家族有相当的同源性，编码CA125的基因被命名为MUC16。MUC16基因的克隆和鉴定为基于分子遗传学的机制评估该分子在卵巢肿瘤中的作用提供了多种新的机会。这个项目的长期目标是检验这样的假设，即MUC16在MUC16的发展和/或维持中发挥关键作用 卵巢癌的恶性表型。这一目标将通过广泛的实验方法来实现，旨在深入了解MUC16在正常发育和细胞生物学以及卵巢上皮细胞肿瘤转化中的功能。本项目的具体目的是：1)对MUC16和Muc16基因的基因组结构进行注释和启动子分析。将对外显子-内含子边界、编码区、非翻译区和转录因子结合位点进行物理和功能表征。2)研究Muc16在体内的功能。在胚胎发育期间以及在新生和成年小鼠以及小鼠卵巢癌中的蛋白表达将是 当与易患浸润性卵巢癌的转基因小鼠杂交时，以时间和组织特异性的方式将Muc16的转基因敲除的效果也将被确定。3)利用已有的关于MUC16表达调控的数据，将隐含的分子途径与启动子结构相关联，验证CA125分泌是MUC16翻译后加工的假设，探索这种加工的机制。4)确定MUC16在人卵巢中的表达是否降低 癌细胞影响肿瘤表型。将使用RNA干扰方法来确定人卵巢癌细胞中MUC16mRNA水平的降低是否会影响细胞的增殖、分化、非锚定生长或体内致瘤性。预计在多种生物学背景下对MUC16功能的研究将被证明是最终阐明该分子在卵巢肿瘤发生中的作用最有效的方法。

The CA125 antigen is a well-characterized serum marker for epithelial ovarian carcinoma and is utilized clinically to monitor response to therapy and recurrence of this malignancy. Recent identification and cloning of a cDNA molecule encoding the core peptide of the CA125 antigen revealed considerable homology to a family of membrane-associated mucins, and the CA125-encoding gene was designated MUC16. The cloning and characterization of MUC16 provides multiple new opportunities for a molecular genetic-based, mechanistic evaluation of the role of this molecule in ovarian neoplasia. The long-term goal of this project is to test the hypothesis that MUC16 plays a critical role in the development and/or maintenance of the malignant phenotype in ovarian carcinoma. This goal will be accomplished through a broad range of experimental approaches designed to gain insight into the function of MUC16 in normal development and cell biology, as well as in the neoplastic transformation of ovarian epithelial cells. The specific aims of this project are to: 1) Annotate the genomic structures and analyze promoters of the MUC16 and Muc16 genes. Exon-intron boundaries, coding regions, untranslated regions and transcription factor binding sites will be characterized physically and functionally. 2) Characterize the function of Muc16 in vivo. Protein expression during embryonic development and in the neonatal and adult mouse and in murine ovarian cancers will be determined, as will the effects of transgenic knockdown of Muc16 in a temporal- and tissue-specific manner when crossed with transgenic mice prone to invasive ovarian carcinoma. 3) Using previously generate data on the regulation of MUC16 expression, correlate implied molecular pathways with promoter structure, and test the hypothesis that CA125 secretion results from post-translational processing of MUC16, exploring the mechanism of this processing. 4) Determine whether a reduction in MUC16 expression in human ovarian carcinoma cells affects the neoplastic phenotype. An RNA interference approach will be used to determine whether reduction of MUC16 mRNA levels in human ovarian carcinoma cells affects cell proliferation, differentiation, anchorage-independent growth or tumorigenicity in vivo. It is anticipated that studies of the function of MUC16 in multiple biological contexts will prove most effective in ultimately elucidating the role of this molecule in ovarian tumorigenesis.