Methylation of the HLA-DR alpha gene is positively correlated with expression
Tóm tắt
We have evaluated the state of methylation of the HLA-DR alpha and HLA-DQ alpha genes in a set of melanoma cell lines which differ in their characteristic expression of these genes and a matching B-cell line. In contrast to the prevailing assumption that genes are methylated when their expression is repressed, we found that one particular site within the first intron of the DR alpha gene is methylated when the cells express HLA-DR or are inducible for its expression. In addition, the HLA-DQ alpha gene may be methylated when it is expressed in a given cell. These findings extend recent observations from other groups that show mixed negative and positive correlations between methylation and class II gene expression, because the cell lines we compared are all from the same individual and, except for the B-cell line, are clonally derived. We tested whether methylation at the identified site was required for expression of the gene by treating the cell lines with the demethylating agent, 5'-azacytidine. Unexpectedly, the treatment actually increases transcription of the DR alpha gene in cell lines already expressing HLA-DR. Possibly other genes that regulate class II expression are demethylated by the treatment and consequently mask any direct effects of the treatment on DR alpha expression. Thus, methylation of the DR alpha gene does not appear to be a simple mechanism for controlling expression. Although our data suggest that methylation of HLA class II genes is not required absolutely for transcription of the DR alpha gene, we believe that chromatin structure in the vicinity of the site may be altered by methylation and thereby exert control.
Tài liệu tham khảo
Accolla, R. S.: Human B cell variants immunoselected against a single la antigen subset have lost expression of several la antigen subsets. J. Exp. Med. 157: 1053–1058, 1983
Albino, A. P., Lloyd, K. O., Houghton, A. N., Oettgen, H. F., and Old, L. J.: Heterogeneity in surface antigen and glycoprotein expression of cell lines derived from different melanoma metastases of the same patient. J. Exp. Med. 154: 1764–1778, 1981
Auffray, C., Lillie, J. W., Arnot, D., Grossberger, D., Kappes, D., and Strominger, J. L.: Isotypic and allotypic variation of the class II human histocompatibility antigen alpha chain genes. Nature 308: 327–333, 1984
Bird, A. P.: DNA methylation—how important in gene control? Nature 307: 503, 1984
Busslinger, M., Hurat, J., and Flavell, R. A.: Methylation and the regulation of globin gene expression. Cell 34: 197–206, 1983
Carrington, M. N., Salter, R. D., Cresswell, P., and Ting, J. P.-Y.: Evidence for methylation as a regulatory mechanism in HLA-DR gene expression. Immunogenetics 22: 219–229, 1985
Compere, S. J. and Palmiter, R. D.: DNA methylation controls the inducibility of the mouse metallothionein-I gene in lymphoid cells. Cell 25: 233–240, 1981
Das, H. K., Lawrence, S. K., and Weissman, S. M.: Structure and nucleotide sequence of the heavy chain gene of HLA-DR. Proc. Natl. Acad. Sci. U.S.A. 80: 3543–3547, 1983
Das, H. K., Lawrence, S. K., and Weissman, S. M.: Structure and nucleotide sequence of the heavy chain gene of HLA-DR. Proc. Natl. Acad. Sci. U.S.A. 80: 7024, 1983
Edelson, R. L. and Fink, J. M.: The immunologic function of skin. Sci. Am. 2: 46–53, 1985
Favaloro, J., Treisman, R., and Kamen, R.: Transcription maps polyoma virus-specific RNA: Analysis by two-dimensional nuclease S 1 gel mapping. Methods Enzymol. 65: 718–749, 1980
Feinberg, A. P. and Vogelstein, B.: A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity. Anal. Biochem. 132: 6–13, 1983
Gambari, R., Del Senno, L., Barbieri, R., Buzzoni, D., Gustafsson, K., Giacomini, P., and Natali, P. G.: Lack of correlation between hypomethylation and expression of the HLA-DR alpha gene. Eur. J. Immunol. 16: 365–369, 1986
Gladstone, P. and Pious, D.: Identification of a trans-acting function regulating HLA-DR expression in a DR-negative B cell variant. Somatic Cell Genet. 6: 285–298, 1980
Houghton, A. N., Thomson, T. M., Gross, D., Oettgen, H. F., and Old, L. J.: Surface antigens of melanoma and melanocytes. J. Exp. Med. 160: 255–269, 1984
Jones, P. A.: Altering gene expression with 5′ azacytidine. Cell 40: 485–586, 1985
Jones, P. A. and Taylor, S. M.: Cellular differentiation, cytidine analogs and DNA methylation. Cell 20: 85–93, 1980
Korman, A. J., Boss, J. M., Spies, T., Sorrentino, R., Okada, K., and Strominger, J. L.: Genetic complexity and expression of human class II histocompatibility antigens. Immunol. Rev. 85: 45–86, 1985
Lee, J. S., Trowsdale, J., and Bodmer, W. F.: cDNA clones coding for the heavy chain of human HLA-DR antigen. Proc. Natl. Acad. Sci. U.S.A. 79: 545–549, 1982a
Lee, J. S., Trowsdale, J., Travers, P. J., Carey, J., Grosveld, F., Jenkins, J., and Bodmer, W. F.: Sequence of an HLA-DR alpha chain cDNA clone and intron-exon organization of the corresponding gene. Nature 299: 750–752, 1982b
Le Gall, I., Marcadet, A., Font, M.-P., Auffray, C., Strominger, J., Lalouel, J.-M., Dausset, J., and Cohen, D.: Exhuberant restriction fragment length polymorphism associated with the DQ alpha chain gene and the DK alpha chain gene. Proc. Natl. Acad. Sci. U.S.A. 82: 5433–5436, 1985
Levine, F. and Pious, D.: Different roles for cytosine methylation in HLA class II gene expression. Immunogenetics 22: 427–440, 1985
Maniatis, T., Fritch, E.F., and Sambrook, J.: Molecular Cloning, A Laboratory Manual, Cold Spring Harbor Laboratory, New York, 1982
McGhee, J. D. and Ginder, G. D.: Specific DNA methylation sites in the vicinity of the chicken beta-globin genes. Nature 28: 419–420, 1979
Peterlin, M. B., Gonwa, T. A., and Stobo, J. D.: Expression of HLADR by a human monocyte cell line is under transcriptional control. J. Mol. Cell. Immunol. 1: 191–200, 1984
Reed, K. C. and Mann, D. A.: Rapid transfer of DNA from agarose gels to nylon membranes. Nucleic Acids Res. 13: 7207–7221, 1985
Reitz, M. S., Jr., Mann, D. L., Eiden, M., Trainor, C. D., and Clarke, M. F.: DNA methylation and expression of HLA-DR alpha. Mol. Cell. Biol. 4: 890–897, 1984
Rigby, P. W. J., Diekmann, M., Rhodes, C., and Berg, P.: Labeling deoxyribonucleic acid to high specific activity in vitro by nicktranslation with DNA polymerase I. J. Mol. Biol. 113: 237–251, 1977
Salter, R. D., Alexander, J., Levine, F., Pious, D., and Cresswell, P.: Evidence for two trans-acting genes regulating HLA class II antigen expression. J. Immunol. 135: 4235–4238, 1985
Solheim, B. G., Moller, E., and Ferrone, S. (eds.): HLA Class II Antigens: A Comprehensive Review of Structure and Function, Springer Verlag, New York, 1986
Sood, A. K., Pereira, D., and Weissman, S. M.: Isolation and partial nucleotide sequence of a cDNA clone for human histocompatibility antigen HLA-B by use of an oligodeoxynucleotide primer. Proc. Natl. Acad. Sci. U.S.A. 78: 616–620, 1981
Spielman, R., Lee, J. S., Bodmer, W. F., Bodmer, J., and Trowsdale, J.: Six HLA-D alpha chain genes on human chromosome six: Polymorphisms and associations of DC alpha-related sequences with DR types. Proc. Natl. Acad. Sci. U.S.A. 81: 3461–3465, 1984
Tonnelle, C., De Mars, R., and Long, E. O.: DO beta: A new beta chain gene in HLA-D with a distinct regulation of expression. EMBO J. 11: 2829–2847, 1985
Trowsdale, J., Lee, J. S., Carey, J., Grosveld, F., Bodmer, J., and Bodmer, W. F.: Sequences related to HLA-DR alpha chain on human chromosome 6: Restriction enzyme polymorphism detected with DC alpha chain probes. Proc. Natl. Acad. Sci. U.S.A. 80: 1972–1976, 1983
Wang, Y. and Peterlin, B. M.: Methylation patterns of HLA-DR alpha genes in six mononuclear cell lines. Immunogenetics 24: 298–303, 1986