Human-mouse hybrids with an embryonal carcinoma phenotype continue to transcribe HLA-A,B,C.
We previously constructed a hybrid cell line, MCP6, which contains an X/6 translocation chromosome as its sole human genetic component in a mouse embryonal carcinoma (EC) cell background. This chromosome, which carries the major histocompatibility complex (MHC) originated from a human B cell which expresses class I and class II MHC antigens. EC cells do not express class I or class II antigens on their cell surface. Northern blot analysis has now shown that in the MCP6 hybrid, human class I genes, i.e., HLA-A,B,C, continued to be transcribed, and cellular levels of the transcripts were similar to, or only slightly lower than, levels in hybrids with a non-EC phenotype. However, very low levels of mRNA species recognised by a mouse class I gene (H-2) probe were also detected in EC cells and EC hybrids. Comparison of the relative levels of H-2 and HLA class I gene transcripts in the EC hybrids and non-EC hybrids indicated that the introduced HLA-A,B,C genes were not appropriately regulated in the EC cell but were subject at least in part to cis control. In contrast to the class I genes, no class II gene (i.e. HLA-DR alpha) transcripts were detected in MCP6. Hybrid EC lines thus provide a system to investigate the different levels of control of MHC gene expression during development and may help to elucidate mechanisms whereby the embryonic genome programs expression of differentiated cell functions.
D000818:Animals; D002906:Chromosomes, Human, 6-12 and X; D005786:Gene Expression Regulation; D006680:HLA Antigens / Q000235:genetics*; D006801:Humans; D006822:Hybrid Cells / Q000502:physiology; D051379:Mice; D010641:Phenotype; D012333:RNA, Messenger / Q000235:genetics; D013724:Teratoma / Q000235:genetics*
D006680:HLA Antigens; D012333:RNA, Messenger