Cytogenetic evidence for the absence of an inactivated X chromosome in a human female (XX) breast carcinoma cell line.
Barr body staining procedures were applied directly to the chamber slide cultures of female amniotic cells. WI38 fibroblasts, normal female kidney cells, and a human breast carcinoma cell line, Elco. A high frequency of Barr bodies was found in all the normal female control cells; however, no Barr bodies were observed in the Elco cells. By trypsin G-banding analysis, two normal X chromosomes were identified in all Elco cells. The late DNA replication pattern of the cell line was then studied with the terminal BrdU pulse method. Both X chromosomes in the Elco cell line were found to be euchromatic with a characteristic R-banding pattern; no late-replicating X chromosome was observed. The absence of both a Barr body and a late-replicating heterocyclic X chromosome provides strong cytogenetic evidence that an inactivated X chromosome is absent in the human breast carcinoma cells bearing two X chromosomes.
D001943:Breast Neoplasms / Q000235:genetics / Q000648:ultrastructure*; D002460:Cell Line; D002871:Chromosome Banding; D004261:DNA Replication; D004273:DNA, Neoplasm; D005260:Female; D006801:Humans; D012728:Sex Chromatin; D014960:X Chromosome / Q000648:ultrastructure
D004273:DNA, Neoplasm