Discovering, mapping and characterization of 39 new genes in human MHC class I region by cDNA selection
The human MHC is located in the short arm of chromosome six covering 3.5-4.0 megabases of DNA. Genes in this complex can be subdivided into three classes according to their structure and function. Recently, more than 40 new genes have been discovered within the class II and class III regions, but the class I region, covering 2 megabases of genomic DNA, has not been extensively studied. In the study presented here, a novel strategy, cDNA hybridization selection, has been applied to investigate the gene content of three yeast artificial chromosomes (YAC) covering about 1 megabase of DNA within the class I region. The results demonstrate that this method was very specific and efficient. It can be used to isolate fragments of cDNA encoded by a given YAC with little or no contamination from ribosomal sequences, repetitive sequences or unique copies of genomic sequences not present in the YAC. Using this strategy, more than 39 new non-class I genes were discovered in the class I region. DNA sequence analysis showed no obvious homology to any known sequences available in the GenEMBL database. Existence of these new genes were further confirmed by isolation of the full length cDNAs from 3 different cDNA libraries; by genomic DNA hybridization, Northern blotting and physical mapping. All of the new genes were mapped to to their own loci. To explore the patterns of gene expression, Northern hybridization was performed with poly-A mRNA from different tissues or cell types. Some of the new genes were specifically expressed in T lymphocytes, some of them only expressed in B lymphocytes, and other strongly expressed either in testis tissues or in Hela cells. These results imply different functions or common features. The B or T lymphocyte specific cDNAs may play some unknown role in the immune system. The biological functions of these novel genes and their relationship with known MHC genes will be of interest for immunologists and cell biologists.
- Research Organization:
- Yale Univ., New Haven, CT (United States)
- OSTI ID:
- 39161
- Country of Publication:
- United States
- Language:
- English
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