Imprinting of insulin-like growth factor 2 is modulated during hematopoiesis.

ABSTRACT

The transcription of insulin-like growth factor 2 (IGF-2) is affected by genomic imprinting, a multistep process through which the parental origin of a gene influences its transcription. The maternal copy of IGF-2 is silenced in most human tissues, but in the choroid plexus and the adult liver both alleles of IGF-2 are expressed. This study shows that though in peripheral blood mononuclear cells IGF-2 shows paternal allele-specific expression, in total bone marrow both alleles are transcribed. This modulation of imprinting is not attributable to use of the P1 promoter, because transcription from the P3 promoter occurred from both alleles. These results suggest that transcriptional recognition of the IGF-2 imprint can be modulated during hematopoiesis and may facilitate the development of in vitro model systems to study the transcriptional recognition of a genomic imprint.