Genomic Ly49A transgenes: basis of variegated Ly49A gene expression and identification of a critical regulatory element.

Several gene families are known in which member genes are expressed in variegated patterns in differentiated cell types. Mechanisms responsible for imposition of a variegated pattern of gene expression are unknown. Members of the closely linked Ly49 inhibitory receptor gene family are expressed in a variegated fashion by NK cells.

Initiation and limitation of Ly-49A NK cell receptor acquisition by T cell factor-1.

The establishment of clonally variable expression of MHC class I-specific receptors by NK cells is not well understood. The Ly-49A receptor is used by approximately 20% of NK cells, whereby most cells express either the maternal or paternal allele and few express simultaneously both alleles. We have previously shown that NK cells expressing Ly-49A were reduced or almost absent in mice harboring a single or no functional allele of the transcription factor T cell factor-1 (TCF-1), respectively.