The discussion centers on the role of Poly-A sequences in relation to reporter genes and the implications of isogenic and null cell lines. Poly-A sequences, typically located downstream of a gene for effective RNA termination and translation, can also be found upstream of a reporter gene. This positioning raises questions about their function, particularly in protecting fused proteins during transcription. The conversation highlights that the Poly-A sequence upstream of a selection marker promoter, such as neomycin resistance, safeguards the mRNA of the fused protein (geneX-LacZ) by ensuring proper transcription and translation. Isogenic cell lines refer to those with similar genomes, while null cell lines are mutants that lack specific traits. The discussion suggests further exploration of these concepts through referenced figures for clarity.
. Upstream means before the promoter. How come?
