KARYOTYPE OF FRIEND VIRUS-INDUCED MOUSE ERYTHROLEUKEMIA-CELLS

Banded karyotypes were prepared for three independent sublines of clone 745A, a Friend virus-induced erythroleukemia cell line originally produced by Dr. C. Friend. Each subline had the same chromosome complement, with a near-diploid number of chromosomes, two-thirds of which appeared normal. The remaining one-third were structurally rearranged marker chromosomes, including eight whose origins could be determined from their banding patterns. A fourth subclone of line 745A, under different selection pressure, showed changes in five marker chromosomes but no changes in the normal chromosomes, suggesting that the markers contained unstable sites, perhaps viral integration sites. Another Friend virus-induced erythroleukemia cell line, FSD-1/F4, developed independently by Dr. W. Ostertag, had a near-diploid number of chromosomes, about one-fourth of which were abnormal chromosomes. The only similarity between these markers and those in subclones of 745A, other than participation of some of the same chromosomes in centric fusion, was the inclusion of the proximal two-thirds of chromosome 15 in one of the markers of each line. This adds to the number of mouse tumor cells or cell lines in which No. 15 is altered or duplicated. In FSD-1/F4 cells there was a striking increase in the size of the secondary constriction of one of the two chromosomes 19, suggesting that the rRNA genes on this chromosome had been amplified. © 1979.