Genomic Amplification of an Endogenous Retrovirus in Zebrafish T-Cell Malignancies

Figure 3

ZFERV amplifications in WT WIK D. rerio T cells. Genomic DNA from 15 WIK lck::EGFP fish was analyzed by qPCR of the ZFERV pol (a) and env (b) genes. White bars depict results from tail DNA of individual fish (lanes 1–6) or groups of 3 fish (lanes 8–10). Black bars show calculated means of 6 singly tested tails (lane 7) or all 15 tails (lane 11). “Tails 7–9” sample (lane 8) was arbitrarily assigned copy number equal to 1, and this DNA was used as the reference standard for all subsequent qPCRs. T cells pooled from 9 or 6 WT fish (gray bars) had 2- to 3-fold gains in ZFERV. Mean copy number was higher in T cells than tailfin DNA for the 15 fish cohort (lane 11 versus 14). Zebrafish elf2a (1 copy/haploid genome) qPCR was used to normalize pol and env results (not shown). Water-only template controls lacked detectable product (not shown). Reactions were performed in triplicate, and error bars show standard deviations (env qPCR of tails 2 and 5 had standard deviations too small to be seen).