MOLECULAR GENETICS OF THE CARBONIC ANHYDRASES

组成哺乳动物的碳酸氢酶(CA)及其相关基因 CA多基因家族代表了一个由八个基因组成的非常不同的组。 这些基因从它们在单个组织中的表达范围(例如，CA VI in 唾液腺)对它们在几乎所有 组织(例如，CA II)。在细胞中，它们存在于：细胞质(CA I，II，III)，与膜相关(CA IV)，分泌颗粒 唾液腺(CA VI)，。或者线粒体的内部基质。因为这样的话 对这些不同CA的具体细胞作用知之甚少 同工酶，基因打靶技术将被用来研究 通过观察不同基因产物的行为， 由特定基因产生的发育、形态或生理效应 小鼠的基因失活。最初，这些基因将被研究谁的 灭活最有可能产生信息丰富的结果。它们是： CA III(主要在骨骼肌中表达)、CA IV(膜- 相关)、CA V(线粒体)和进化高度保守的 CA相关蛋白，鲤鱼。提出了以下具体目标：(L) 进行靶向构建并产生具有突变的ES细胞系 选定的四个小鼠基因，(2)产生纯合子缺陷小鼠 对于每个基因，(3)定位CA基因的染色体位置 尚未映射的(CA IV、CA V和CAPP)，以及(4)生成 多个CA基因联合缺陷小鼠检测 职能重叠。如果时间允许，将进行类似的研究 在其他CA基因上，CA I，CA VI和CA VII。除了 阐明基因产物的功能、CA的其他方面 有缺陷的老鼠将是非常有用的。例如，如果一个 纯合CA缺陷小鼠类似于一种遗传性人类疾病 未知的遗传病因，有可能相同的CA缺乏症 为人类疾病负责，从而提供了一个有用的动物模型 人类疾病的治疗。此外，确定 这些基因的染色体位置可能是一种自发的 特定CA基因的突变可能是导致经典的 小鼠的表型突变。这种自发突变，无论是 活动的完全缺陷或部分丧失，可以提供洞察力 研究受影响基因的生物学功能。

The carbonic anhydrase (CA) and CA-related genes comprising the mammalian CA multigene family represent a remarkably diverse group of eight genes. These genes range from in their expression single tissues (e.g., CA VI in salivary glands) to their expression in certain cells of virtually all tissues (e.g., CA II). In the cell, they are found in: the cytoplasm (CA I, II, III), associated with membranes (CA IV), the secretory granules of salivary glands (CA VI),. or the inner matrix of mitochondria. Because so little is known about the specific cellular roles of these different CA isozymes, the technique of gene targeting will be used to investigate the functions of the different gene products by observing the behavioral, developmental, morphological or physiological effects produced by specific gene inactivations in mice. Initially, those genes will be studied whose inactivations are most likely to produce informative results. These are: CA III (expressed primarily in skeletal muscle), CA IV (membrane- associated), CA V (mitochondria), and the highly evolutionarily-conserved CA-related protein, CARP. The following specific aims are proposed: (l) to make targeting constructs and generate ES cell lines with mutations in the four selected mouse genes, (2) to generate homozygous mice deficient for each of the genes, (3) to map the chromosomal location of the CA genes that are not already mapped (CA IV, CA V and CARP), and (4) to generate mice with combined deficiencies for multiple CA genes in order to detect overlapping functions. If time permits, similar studies will be carried out on the other CA genes, CA I, CA VI and CA VII. In addition to elucidating the functions of the gene products, other aspects of the CA deficient mice will be highly useful. For example, if the phenotype of a homozygous CA deficient mouse is similar to an inherited human disease of unknown genetic etiology, it is possible that the same CA deficiency is responsible for the human disorder thereby providing a useful animal model for the human disease. Also, an important reason for determining the chromosomal locations of these genes is the possibility that a spontaneous mutation in a specific CA gene may be responsible for one of the classical phenotypic mutants of the mouse. Such spontaneous mutations, whether complete deficiencies or partial losses of activity, can provide insight into the biological function of the affected gene.