Peelman L J, Mattheeuws M, Van Zeveren A, van de Weghe A, Bouquet Y
Department of Animal Nutrition, Genetics, Breeding and Ethology, Faculty of Veterinary Medicine, University of Ghent, Belgium.
Anim Genet. 1996 Feb;27(1):35-42. doi: 10.1111/j.1365-2052.1996.tb01174.x.
The RD gene, named after the arginine (R) and aspartic acid (D) repeat in the central part of its protein, was initially mapped in the mouse H-2S subregion between C4 and BF. It was later mapped in the same position in the human MHC and here we show it is also conserved in the pig MHC class III region, close to the complement BF gene. A pig RD genomic clone was isolated from a lambda-phage library. Hybridizations on genomic DNA separated with pulsed field gel electrophoresis identified common 220 kb NruI, 130 kb EagI and 200 kb MluI bands for RD, BF and C2. The RD gene has also a 17 kb Kp nI and 11 kb SacI fragment in common with BF but not with C2. The close linkage of the RD and BF genes was further established by hybridization of BF to a genomic lambda-phage clone also containing the RD gene. This genomic RD clone overlaps with a lambda-phage clone previously isolated and containing the complete BF gene and the 3' part of C2. The distance between RD and BF is about 6 kb. The junction between the two complement genes BF and C2 was sequenced and the BF 5' promoter region, overlapping the 3' noncoding region of C2, was compared with that of the human BF promoter. The overall homology was about 80% and all but one identified promoter elements were found in the same position in both genes. The results obtained demonstrate the RD-BF-C2 organization is strongly conserved between human, mouse and pig. No polymorphisms were detected in either the RD gene or in the BF promoter region using polymerase chain reaction and restriction fragment polymorphism analysis.
RD基因因其蛋白质中部的精氨酸（R）和天冬氨酸（D）重复序列而得名，最初定位于小鼠H-2S亚区的C4和BF之间。后来在人类MHC的相同位置定位，我们在此表明它在猪MHC III类区域也保守，靠近补体BF基因。从λ噬菌体文库中分离出一个猪RD基因组克隆。用脉冲场凝胶电泳分离的基因组DNA杂交鉴定出RD、BF和C2常见的220 kb NruI、130 kb EagI和200 kb MluI条带。RD基因还与BF有一个17 kb的KpnI和11 kb的SacI片段相同，但与C2不同。通过将BF与一个也包含RD基因的基因组λ噬菌体克隆杂交，进一步确定了RD和BF基因的紧密连锁。这个基因组RD克隆与先前分离的一个λ噬菌体克隆重叠，该克隆包含完整的BF基因和C2的3'部分。RD和BF之间的距离约为6 kb。对两个补体基因BF和C2之间的连接处进行了测序，并将与C2的3'非编码区重叠的BF 5'启动子区域与人BF启动子进行了比较。总体同源性约为80%，除一个外，所有已鉴定的启动子元件在两个基因的相同位置都能找到。所得结果表明，RD-BF-C2的组织在人、小鼠和猪之间高度保守。使用聚合酶链反应和限制性片段多态性分析，在RD基因或BF启动子区域均未检测到多态性。
