What does it mean: carrying the stably integrated gene Reading this study < They writing > Multiple **exogenous** and endogenous genes can be simultaneously activated by CRISPR-on > > We tested single, double and triple activation of a TetO::tdTomato transgene and the endogenous SOX2 and IL1RN genes (Figure 3A) in HEK293T cells carrying the stably integrated TetO::tdTomato transgene Could you please help me to understand: They talking about exogenous gene. But saying "carrying the stably integrated". Does that mean that this gene (TetO::tdTomato) is in the cell genome (integrated to genome)? If so, what is the meaning of exogenous here? Thank you!

According to Merriam Webster, an exogeneous gene is defined as " introduced from or produced outside the organism or system; specifically : not synthesized within the organism or system—compare endogenous".

I believe they refer to the tetO::tdTomato transgene as an exogeneous, or not originating from the species of study