Stable Lyonization of X-linked pgk-1 gene during aging in normal tissues and tumors of mice carrying Searle's translocation.
We investigated whether age-dependent reactivation of a repressed X-linked gene occurs. Subjects were female mice, carrying the X-autosomal translocation, T(X;16)16H (Searle's translocation). The mice were also heterozygous, for the X-linked gene coding for phosphoglycerate kinase (T16H pgk-1b/+ pgk-1a and pgk-1a was selectively repressed in these mice (McMahon and Monk, 1983). An electrophoretic method was applied to determine the PGK-1 allozyme patterns in blood, bone marrow, brain, gastrointestinal tract, liver, heart, spleen, and uterus (including tumor tissues when found). Samples were collected from mice of three different ages: 2 months (n = 4), 11 to 12 months (n = 10), or 18 to 21 months (n = 15). The lowest detection limit of the relative cellular population expressing the PGK-1A allozyme was found to be 2%, which was sensitive enough to detect the reported reactivation ratio (more than 10% of cells in a lower power microscopic field). We could not detect PGK-1A activity in any organ, including tumors in any age group, leading to the conclusion that reactivation of the repressed pgk-1a gene did not occur during aging.
Tsukada
M
M
Department of Hygiene, Akita University School of Medicine, Japan.
Wada
Y
Y
Hamade
N
N
Masuda
H
H
Koizumi
A
A
D000375:Aging / Q000235:genetics*; D000818:Animals; D001921:Brain / Q000201:enzymology; D004586:Electrophoresis; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D008040:Genetic Linkage / Q000235:genetics*; D005838:Genotype; D008099:Liver / Q000201:enzymology; D051379:Mice; D008809:Mice, Inbred C3H; D008815:Mice, Inbred Strains; D009206:Myocardium / Q000201:enzymology; D009374:Neoplasms, Experimental / Q000201:enzymology; D010641:Phenotype; D010735:Phosphoglycerate Kinase / Q000032:analysis / Q000097:blood / Q000145:classification / Q000235:genetics*; D013154:Spleen / Q000201:enzymology; D014178:Translocation, Genetic / Q000235:genetics*; D014599:Uterus / Q000201:enzymology; D014960:X Chromosome
D010735:Phosphoglycerate Kinase