Expression of fragile X in human-mouse somatic cell hybrids.
Fragile X expression was studied in human-mouse cell hybrids prepared from lymphocytes and fibroblasts obtained from a mentally retarded male. The patient showed a fragile X in 29-35.5% of his lymphocytes in medium 199 (M199) and in M199 plus fluorodeoxyuridine (FdU). One lymphocyte hybrid clone showed no expression in M199 and low expression in M199 + FdU. The other lymphocyte hybrid clone showed significantly increased expression in both media, comparable to levels in the parental cells. Fibroblast cultures from the patient showed no fragile X expression in M199 and 17% expression in M199 + FdU. Fragile X expression was also found in fibroblast hybrid clones in M199 and was significantly enhanced by the addition of FdU. Fragile X expression in one clone was consistently lower than in the other two clones and in the parental fibroblasts. Our results indicate that the level of fragile X expression varies in the hybrid clones, since frequencies similar to those of parental cells and suppressed frequencies were found. The presence or absence of a specific human chromosome did not correlate with the level of fragile X expression.
D000818:Animals; D002871:Chromosome Banding; D005347:Fibroblasts / Q000648:ultrastructure; D005600:Fragile X Syndrome / Q000235:genetics*; D006801:Humans; D006822:Hybrid Cells; D007621:Karyotyping; D008214:Lymphocytes / Q000648:ultrastructure; D008297:Male; D051379:Mice; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014960:X Chromosome