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Sehgal, Devinder; Johnson, George; Wu, Tai T.; Mage, R. G.
doi: 10.1007/s002510050683pmid: 10541804
In mouse and human, generation of combinatorial diversity through use of different heavy and light chain variable region genes in immunoglobulin rearrangements can be a major contributor to the primary antibody repertoire. In rabbits, the contribution of the combinatorial mechanism to heavy chain diversity is minimal, as only a few Igh-V genes are rearranged and expressed. To investigate the contribution of combinatorial diversity toward generation of the rabbit Vκ repertoire, we constructed five genomic libraries from rabbit kidney DNA and 1 cDNA library from the bone marrow of a 1-day-old rabbit using a series of polymerase chain reaction-based strategies. Our analyses indicate that most of the sequences that we recovered from our libraries belong to a single family and some are extremely similar. The actual number of germline Igk-V genes is potentially greater than our conservative estimate of at least 39, 28 of which we found expressed as mRNA. The germline Igk-V genes display different lengths of the coding region 3′ of Cys 88 ranging from 7 to 12 amino acids, resulting in CDR3 length heterogeneity among functional VκJκ sequences ranging from 8 to 15 amino acids. Some of the VκJκ junctions had N and P nucleotide additions. Thus, in contrast to limited combinatorial diversity of its heavy chain, the rabbit can draw upon a diverse set of germline Igk-V genes. The κ light chain has the potential to be a major contributor toward generation of the antibody specificities of the rabbit pre-immune repertoire.
Katagiri, Takayuki; Hirono, Ikuo; Aoki, T.
doi: 10.1007/s002510050684pmid: 10541805
The amino acid sequences of the human terminal complement components show extensive structural similarity to each other. In this study the C8β and C9 cDNAs of Japanese flounder, Paralichthys olivaceus, were cloned and analyzed. The derived deduced amino acid sequences of the two terminal components were homologous to those of humans, in that the sequences of both species contained LDL receptor, EGF precursor, and two thrombospondin domains. Japanese flounder C9 was found to have a second thrombospondin region in the C-terminus, similar to that reported for rainbow trout and pufferfish. Moreover, these two complement component cDNAs of Japanese flounder had partial similarity to human perforin. These findings show that Japanese flounder C8β and C9 have similar structures, which supports the hypothesis that the terminal complement genes originated from the same ancestral gene. Collectively, these features emphasize the strong similarity among the members of the terminal complement family.
Collec, Emmanuel; Colin, Yves; Carbonnet, Florence; Hattab, Claude; Bertrand, Olivier; Cartron, Jean Pierre; Le Van Kim, C.
doi: 10.1007/s002510050681pmid: 10541802
The human Kx blood group antigen is carried by a 37 000 M r apparent molecular mass membrane polypeptide which is deficient in rare individuals with the McLeod syndrome. The X-linked human XK gene is transcribed in many tissues including adult skeletal muscle and brain, sieges of disorders observed in McLeod syndrome. We report here the cloning of the orthologous mouse XK mRNA. Comparison of XK from human and mouse revealed 80% sequence similarity at the amino acid level. The mouse XK gene is organized in two exons and is expressed in many tissues, but its expression pattern is slightly different from that of the human gene. The presence in mouse erythrocyte membrane of a 43 000 M r Kx-related protein was demonstrated by immunoblotting with a rabbit antiserum directed against the human protein. With non-reduced samples, a 140 000 M r species was detected instead of the 43 000 M r protein, suggesting that, as demonstrated in the Kx polypeptide might be complexed with another protein in mouse red cells, presumably the homologue of the human Kell protein of 93 000 M r.
Saeij, Jeroen P. J.; Wiegertjes, G. F.; Stet, René J. M.
doi: 10.1007/s002510050686pmid: 10541807
The mouse Lsh/Ity/Bcg locus regulates natural resistance to intracellular pathogens, and the Nramp1 gene was isolated as its candidate. Nramp is part of a small family of at least two genes, Nramp1 and Nramp2. In the present study, a full-length cDNA for carp NRAMP has been isolated and characterized. Nucleotide and predicted amino acid sequence analysis indicate that the carp NRAMP encodes a 548 amino acid membrane protein with 12 putative transmembrane domains, two N-linked glycosylation sites, and an evolutionarily conserved consensus transport motif. The peptide sequence identity among carp and human NRAMP2 is 78%, and 65% with human NRAMP1. Reverse transcription-polymerase chain reaction revealed that carp NRAMP is ubiquitously expressed. Phylogenetic analysis, using neigbor-joining, showed that the carp NRAMP protein clustered together with mammalian NRAMP2 proteins.
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