Zebrafish DANA retroposon can form large zebrafish sequence in human Hepg2 and 293T cell lines

Abstract

AbstractIn this study, we cloned small zebrafish retroposon DANA from zebrafish genome and constructed the lentiviral expression vector pEB-GFP (T2A)PURO. Three human cell lines including 293T, Hepg2 and LO2 were selected as infection targets. After detecting the expression of DANA, we found that the expression of DANA retroposon in three cells had different effects on cell lines through chromosome walking. Among these cells, LO2 showed no DANA retrotrans-position, while 293T and Hepg2 cell lines displayed retrotrans-position with the formation of some zebrafish genome fragments. Thereafter, we constructed a mutant of DANA retroposon and infected it in 293T cells, but no retrotrans-position was found after chromosome walking. Re-sequencing of the two cell lines (293T and Hepg2) showed that a large number of zebrafish genome fragments were found in the genomes of both cell lines, which could be divided into four types. The first type was zebrafish microsatellite sequence, accounting for 79.23% and 74.45% in 293T cell line and Hepg2 cell line, respectively. The second type was the sequence with a small amount of poly A or T, and the third type was the sequence with poly G or C, and the second and third types accounted very low proportion. The fourth type was composed of coding sequence and non-coding sequence, with large difference and very low proportion of common sequences between the two cell lines. Taken together, this study indicated that zebrafish DANA retroposon can result in retrotrans-position using the retrotrans system of human cell lines.