REGULATED SYNTHESIS OF SIALYLTRANSFERASES

糖蛋白和糖蛋白的正确糖基化是公认的 糖脂是高血压正常发育和维持的基础 动物。然而，人们对其结构和功能知之甚少 低聚糖链的相互关系及其调控 表情。在组成碳水化合物链的糖中，唾液酸 酸，仅以末端糖的形式存在，可能是最广泛的， 尽管不完全，但已经研究过了。这是这个项目的长期目标 阐明决定组织和发育的途径 糖偶联物上唾液酸部分的特异性。 至少需要五种唾液酸转移酶，而且很可能更多。 哺乳动物体内主要唾液酸键的生物合成 糖蛋白。然而，先前对唾液酸功能的分析 酸和唾液酸转移酶的调节表达受到阻碍 由于缺乏可用于特定分子探针的序列信息 建造的。这个实验室和其他实验室的努力导致了 肝脏β-半乳糖苷α2，6-半乳糖苷的序列分析 唾液酸转移酶的mRNA是通过糖皮质激素途径调节的。 该实验室目前的观察还发现了一个家族 与肝脏α2，6-唾液酸转移酶基因密切相关的转录本 并表现出特定于组织的表达模式。至少在这些中 相关转录本推测编码一个不同的多肽序列。 这项研究的一个直接目标是详细描述 这个家庭的不同成员以及对关系的评估和 个体成绩单的遗传来源。随后， 功能以及体内和体外合成模式 这些转录本和多肽将被解决。与之平行的目标 这项研究阐明了调控细胞周期的调控途径 唾液酸转移酶相关转录本家族的表达。对这件事 最后，必要的调控序列将由 嵌合结构的表达。

It is well established that correct glycosylation of glycoproteins and glycolipids is fundamental to normal development and maintenance of higher animals. However, little is known about the structural and functional relationship of the oligosaccharide chains and the regulation of their expression. Among the sugars that comprise the carbohydrate chains, sialic acid, present only as the terminal sugars, is perhaps the most extensively, albeit incompletely, studied. It is the long ranged goal of this project to elucidate the pathways that determine the tissue and development specificities of sialic acid moieties on glycoconjugates. At least five, and most likely more, sialytransferases are required in the biosynthesis of the major sialic acid linkages found in mammalian glycoproteins. However, previous analysis of the functionality of sialic acids and the regulated expression of sialytransferases has been hampered by lack of sequence information from which specific molecular probes can be constructed. Efforts from this and other laboratories resulted in the sequence elucidation of the hepatic beta-galactoside alpha2,6- sialytransferase mRNA is modulated via the glucocorticoid pathway. Current observations from this laboratory has also uncovered a family of transcripts closely related to the hepatic alpha2,6-sialytransferase mRNA and exhibit a tissue specific pattern of expression. At least on of these related transcripts putatively encodes a divergent polypeptide sequence. An immediate objective of this study is a detailed characterization of the different members of this family and an assessment of the relationship and genetic origin of the individual transcripts. Subsequently, the functionality as well as in vivo and in vitro patterns of synthesis of these transcripts and polypeptides will be addressed. A parallel goal of this study is the elucidation of regulatory pathways that govern the expression of this family of sialytransferase related transcripts. To this end, requisite regulatory sequences will be identified and tested by the expression of chimeric constructs.