Parental influences on expression of glucose-6-phosphate dehydrogenase,G6pd, in the mouse; a case of imprinting

Abstract

Glucose-6-phosphate dehydrogenase (G6PD) activity was measured in blood from heterozygotes for the normal allele G6pda and the low activity allele G6pda-mlNeu. In adult mice lower activity was found in G6pda/G6pda-mlNeu than in the reciprocal heterozygote G6pda-mlNeu/G6pda (the maternal allele being listed first). Thus, either the paternally derived allele was over-expressed or the maternally derived allele was under-expressed. By contrast, in younger mice the difference in G6PD activity in reciprocal crosses was less marked. The findings are interpreted in terms of differential imprinting of maternally and paternally inherited information. The explanation offered for age related differences is that, as a consequence of imprinting, either the paternal X-chromosome is preferentially reactivated, or cells in which the paternally derived allele is active are at a selective advantage, and proliferate better than those in which the maternally inherited allele is active.

Two-dimensional electrophoretic protein patterns of reciprocal hybrids of the mouse strains DBA and C57BL

“…These investigations were concerned with the asynchronous activation of parental alleles of enzyme loci in the early development of amphibians Moyer, 1966, 1968) and fish (Hitzeroth et al, 1968;Klose et al, 1969;Ohno, 1969;Klose and Wolf, 1970;Whitt et al, 1972Whitt et al, , 1973Schmidtke et al, 1976). Recently, the reciprocal F1 progenies of two mouse strains differing in the activity of the X-linked enzyme glucose-6-phosphate dehydrogenase (G-6-PD) were compared, and a preferential transmission of the paternal activity was found (Peters and Ball, 1990). In contrast to the investigations on single enzymes, twodimensional electrophoresis of proteins from complex tissue extracts may allow us to analyze hundreds of proteins from different classes with regard to genomic imprinting (Klose and Reik, 1992).…”