Characterization of a tobacco bright yellow 2 cell line expressing the tetracycline repressor at a high level for strict regulation of transgene expression

Manipulating the expression of a transgene in transient and stable transfor med cells is a requirement for many functional analyses. We have investigat ed the use of the tetracycline-dependent gene expression system developed b y Gatz et al. (1992) in tobacco (Nicotiana tabacum L. cv Bright Yellow 2 [B Y2]) cells, the most widely used plant cell culture. We have selected a BY2 cell line, named BY2-tetracycline repressor (tetR) 17, which expresses the tetR at a high level, and have evaluated the capacity of this cell line to suppress the expression of a green fluorescent protein reporter gene under the control of the "Triple-Op" promoter in the absence of tetracycline in a large number of independent transformants. The ability to induce the expr ession of green fluorescent protein after treatment by anhydrotetracycline in the same transformants was also analyzed. BY2-tetR17 cells were demonstr ated to be excellent recipient cells for recovery of clonal cell lines with a highly controlled regulation of the introduced transgene.