Ideas about these questions, please. - (Mar/22/2005 )

Ideas about these questions, please.

#Why is Poly-A sequence upstream of a reporter gene?
#Isogenic cell lines?
#Null cell lines?

Thanks.

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hi

poly a sequence upstream a reporter gene is for ensuring the good RNA termination, and translation.
isogenic cell lines are cell lines that have the same genetic background but differs from 1 gene
null cell lines are cells that have been knocked down for a locus.

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Usually the poly A sequence lays downstream of a gene to give it good RNA termination and translation. BUt when it lies upstream is something new . Upstream means before the promoter. How come?

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