Biallelic methylation and silencing of mouse Aprt in normal kidney cells.
Heritable gene silencing is an important mechanism of tumor suppressor gene inactivation in a variety of human cancers. In the present study, we show that methylation-associated silencing of the autosomal adenine phosphoribosyltransferase (Aprt) locus occurs in primary mouse kidney cells. Aprt-deficient cells were isolated from mice that were heterozygous for Aprt, i.e., they contained one wild-type Aprt allele and one targeted allele bearing an insertion of the bacterial neo gene. Although silencing of the wild-type allele alone was sufficient for the cells to become completely Aprt-deficient, biallelic methylation of the promoter region was found to occur. Moreover, despite the absence of selective pressure against the targeted allele, phenotypic silencing of the inserted neo gene accompanied silencing of the wild-type Aprt allele. A potential role for allelic homology in these events is discussed.
Center for Research on Occupational and Environmental Toxicology, Oregon Health Sciences University, Portland 97201, USA.
J A
JA
Rose
P A
PA
Yates
J
J
Simpson
J A
JA
Tischfield
P J
PJ
Stambrook
M S
MS
Turker
D000225:Adenine / Q000494:pharmacology; D000228:Adenine Phosphoribosyltransferase / Q000235:genetics*; D000818:Animals; D001377:Azaserine / Q000494:pharmacology; D002999:Clone Cells; D019175:DNA Methylation; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D006579:Heterozygote; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000172:deficiency / Q000235:genetics; D019868:Kanamycin Kinase / Q000235:genetics; D007668:Kidney / Q000201:enzymology*; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping
D001377:Azaserine; D000228:Adenine Phosphoribosyltransferase; D007041:Hypoxanthine Phosphoribosyltransferase; D019868:Kanamycin Kinase; D000225:Adenine