Analysis for putative relationship between causative genes for hereditary disorder and quantitative traits loci in cattle

对R664 X突变导致的带3缺陷的表型与主要影响牛肉风味和口感的饱和/不饱和脂肪酸含量之间的关系进行了评估。表型/基因型和牛肉品质之间没有直接联系，虽然带3缺陷的载体似乎有不饱和脂肪酸，如油酸的水平高于正常动物。此外，我们不能获得直接的证据，显着优势的纯合/杂合状态的claudin-16缺陷。目前的研究表明，位于19号染色体上的一个遗传因子可以调节脂肪酸的含量，并提示它与脂肪坏死有关。带3缺陷的分子病理学研究结果表明，带3突变体（bebRX）对正常带3和膜骨架中的配偶体锚蛋白的表达起显性负性作用，在红系发育过程中，带3合成开始后不久，带3与锚蛋白的相互作用就发生在ER膜上。红系细胞和肾小管细胞中带3的全部或部分缺乏似乎引起酸中毒，导致细胞代谢下调。在MDCK细胞中表达的Claudin-16显示出包括钙离子在内的离子和溶质的细胞旁转运的总体减少，而它似乎形成钙的细胞间途径，这表明claudin-16和除claudin-1/4之外的其他claudin蛋白质的异嗜性组合对于钙的分子孔的形成是必不可少的。

A putative relationship between phenotypes for band 3 deficiency with the R664X mutation and contents of saturated/unsaturated fatty acids, which predominantly affect flavor and taste of beef, was evaluated. There was no direct linkage between phenotype/genotype and beef quality although carriers for band 3 deficiency appeared to have unsaturated fatty acids such as oleic acid at levels higher than normal animals. Moreover, we could not obtain direct evidence for remarkable advantage of homozygous/heterozygous states for claudin-16 deficiency. Present study, however, demonstrated a genetic factor that would regulate fatty acid contents located in chromosome 19, and suggested its linkage with fatnecrosis.The findings on molecular pathobiology of band 3 deficiency indicated that the mutant band 3 (bebRX) plays a dominant-negative role on the expression of normal band 3 and a partner in the membrane skeleton, ankyrin, and the interaction of band 3 with ankyrin occurs on the ER membrane soon after band 3 synthesis is started during erythroid development. Total or partial deficiency of band 3 in erythroid and renal tubular cells appeared to cause acidosis, leading to downregulation of cell metabolism. Claudin-16 expressed in MDCK cells displayed overall reduction in paracellular transport of ions and solutes including calcium ion, while it appeared to form intercellular pathway for calcium, suggesting that heterophilic combinations of claudin-16 and other claudin proteins other than claudin-1/4 would be essential to formation of molecular pores for calcium.