Detection of protein binding to a glucocorticoid response element-like sequence in a chicken major histocompatibility complex class II promoter

The glucocorticoid response element in gene promoters mediates regulation o f gene expression by glucocorticoids. The major histocompatibility (MHC) cl ass II genes, crucial for immunoresponsiveness, are among those modulated b y glucocorticoids. A GRE-lilke sequence has been located in the promoter of a chicken MHC class II promoter. DNase footprinting revealed protein bindi ng by the GRE-like sequence when nuclear extract from chicken T or B cell l ines were used. Gel shift assays detected multiple binding activities in th e lymphocyte cell lines, but little binding in the macrophage cell line. Re lative band intensity differed among the lymphocyte cell lines. By using a mutant GRE oligonucleotide, most of the binding activities were demonstrate d to be specific to the GRE. This study suggests a role of the GRE-like seq uence in regulating chicken MHC class II genes and provides further evidenc e for the previously reported influence of glucocorticoids on chicken MHC c lass II expression which may be the molecular basis of glucocorticoid immun omodulation. (C) 2000 Elsevier Science B.V. All rights reserved.