Construction and expression of gene families

人们一直认为，最原始的产生抗体的动物是回旋虫。分离编码盲鳗“抗体”的基因，确定其核苷酸序列。令人惊讶的是，这个基因编码的不是免疫球蛋白，而是补体C3。我们建立了一种分离原始脊椎动物MHC基因的新方法。通过这种方法，我们成功地从鲤鱼中分离出MHC类i和分类β基因，并从鲨鱼中分离出MHC类i基因。我们还发现，在硬骨鱼的水平上，MHC i类基因已经扩展到至少几十个，并且它们的序列相当异质。我们检查了来自不同动物门的含有同源盒的基因。从海绵中分离到两个同源盒基因prox1和prox2。prox1和prox2的结构表明它们已经获得了从高等动物中分离出来的每一类同源盒基因的特性特征。从水螅中分离到4个同源盒型基因。从秀丽隐杆线虫中鉴定出一种新的同源盒型基因。从人体内分离到两种新的同源盒型基因GBX1和GBX2。我们将GBX1定位到染色体7q36.1上。

It has been believed that the most primitive animal that produces antibodies is cyclostome. We isolated the gene which encodes hagfish "antibodies" and determined the nucleotide sequence. Surprisingly, it turned out to be a gene encoding not immunoglobulin but complement C3. We developed a new method using PCR for isolation of MHC genes from primitive vertebrates. By this method, we have succeeded to isolate genes encoding MHC classI and classIIbeta from carp and also a gene encoding MHC classI from shark. We also showed that at the level of bony fish MHC classI genes have been expanded to at least several tens and their sequences are quite heterogeneous.We examined homeobox-containing genes from various phyla of animals. We isolated two homeobox genes, prox1 and prox2 from sponge. The structure of prox1 and prox2 indicated that they have gained the properties characteristics for each class of homeobox genes isolated from higher animals. We isolated four homeobox genes from hydra. A new kind of homeobox gene was identified from C. elegans. Two kinds of new homeobox genes, GBX1 and GBX2, were isolated from human. We mapped GBX1 to chromosome 7q36.1.