Oncofetal splice-pattern of the human H19 gene.

H19 is an imprinted gene that demonstrates maternal monoallelic expression in fetal tissues and in some cancers, and very likely does not code for a protein. H19 is involved in the regulation of cell proliferation, embryonic growth, and differentiation through upstream and downstream cis elements that influence the expression of IGF2, a closely physically linked gene, and also through its RNA involved in metastasis and angiogenic processes. We report the identification of an alternatively spliced variant of H19 RNA that lacks part of exon 1. This variant was detected in human embryonic and placental tissues, but not in bladder or hepatocellular carcinomas. A very low level of this variant was also detected in colon carcinoma. The observed pattern of expression suggests that this splice variant is a developmentally regulated H19 gene transcript.