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Title: Tissue specificity and variability of imprinted IGF2 expression in humans

Parental genomic imprinting refers to the phenomenon where expression of a gene copy depends on the sex of the parent from which it is derived. The human insulin-like growth factor II gene, IGF2, is parentally imprinted with the paternal gene copy exclusively expressed in fetal and term placenta as well as in fetal kidney. In mice, imprinted IGF2 expression is tissue-specific. In a preliminary approach to investigate tissue-specific IGF2 imprinting in humans, we evaluated allele-specific expression in four samples of umbilical cord blood leukocytes of fetuses found to imprint IGF2 in placenta. IGF2 mRNA transcripts from the gene copy transmitted from each parent were distinguished using a transcribed ApaI polymorphism by performing reverse transcription-PCR on total RNA from cord blood leukocytes. Postnatal peripheral blood was examined using the same method. Of 77 informative individuals, 68 expressed both IGF2 copies, but 9 individuals showed unambiguous monoallelic expression. Two individuals from each category were screened again and the results were identical. These data indicate that imprinted IGF2 expression is tissue-specific and show variability of IGF2 imprinting among individuals. This variability may be genetic. We are in the process of screening large pedigrees to test this hypothesis.
Authors:
; ;  [1]
  1. McGill Univ., Quebec (Canada)
Publication Date:
OSTI Identifier:
134620
Report Number(s):
CONF-941009--
Journal ID: AJHGAG; ISSN 0002-9297; TRN: 95:005313-1357
Resource Type:
Journal Article
Resource Relation:
Journal Name: American Journal of Human Genetics; Journal Volume: 55; Journal Issue: Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; GENES; GENETIC VARIABILITY; GENE REGULATION; TISSUE DISTRIBUTION; TRANSCRIPTION; GENETICS; SEX DEPENDENCE; GROWTH FACTORS; MICE; LEUKOCYTES; PLACENTA; POLYMERASE CHAIN REACTION; MESSENGER-RNA