INFLUENCE OF GENE DUPLICATION AND X-INACTIVATION ON MOUSE MITOCHONDRIAL MALIC ENZYME ACTIVITY AND ELECTROPHORETIC PATTERNS

[摘要] We have investigated, with and without the influence of X -inactivation, the relationship between autosomal gene-dosage and gene-product in a mammalian system, the mouse. The gene was mitochondrial malic enzyme ( Mod-2 ), shown to lie on Chromosome 7 between the albino ( c ) and shaker-1 ( sh-1 ) loci, and the enzyme was its product, mitochondrial malic enzyme (MOD-2). Gene duplication, with and without the influence of X -inactivation, was achieved using a translocation that involves the insertion of a portion of Chr 7 , including Mod-2 , into the X, T(X;7)1Ct . A 1:1 relationship for Mod-2 dosage and MOD-2 activity was found in heart mitochondria. Evidence of X -inactivation of Mod-2 was noted in heart and kidney preparations from females carrying a Mod-2 duplication (one copy of Mod-2 in the X and two copies of Mod-2 on Chr 7 ). We conclude that the expression of an autosomal locus attached to X -chromatin depends upon whether the translocation is in a balanced or unbalanced state.

[学科分类] 医学（综合）