Absence of MHC gene expression in lens and cloning of dbpB/YB-1, a DNA-binding protein expressed in mouse lens

Abstract

The status of major histocompatibility complex (MHC) class I and II gene expression in the normal mouse lens was examined. No mRNA for either class I or II genes was detectable in mouse lens, while the expression of MHC genes in other tissues generally matched immunohistochemical data from human tissues. However it was observed that MHC class I mRNA is present in the mouse lens-derived cell line aTN4-l. From a new-born mouse lens cDNA library a clone was obtained for the murine homologue of the DNA-binding protein dbpB/YB-1, a protein originally identified in human lymphocytes and proposed to be a negative regulator of MHC class II gene expression. Northern blots detect dbpB/YB-1 mRNA in all mouse tissues and cells examined, including both mouse lens and QTN4-1 cells, suggesting that dbpB/YB-1 has a general and widespread role.