Expression of insulin-like growth factor II (IGF)-II) and H19 in murine teratocarcinomas derived from embryonic stem (ES) cells.

Insulin-like growth factor II (IGF-II) is expressed during embryogenesis in rodents and humans, but is not produced in most adult tissues. This pattern of expression is closely shared by the gene H19, which lies 3' to IGF-II. This, together with the fact that the genes are reciprocally imprinted, has led to the proposal that the genes are under common transcriptional control by the H19 enhancers during development. In the present study, embryonic stem (ES) cells have been used to generate teratocarcinomas in mice. These tumours generate a wide range of differentiated tissues which have been subjected to hybridisation histochemistry with RNA probes to H19 and IGF-II. Coexpression of the two genes was found in a range of tissues, a pattern consistent with the idea of common transcriptional control. However, there were some areas in which H19 was expressed strongly in comparison with IGF-II and vice versa suggesting the existence of further control elements other than the H19 enhancers.