Reducing or eliminating expression of a given gene is likely to require multiple methods to ensure coverage of all of the genes in a given @entity1 cell. We and others [Furth, P. A., Choe, W. T., Rex, J. H., Byrne, J. C., and Baker, C. C. (1994) Mol. Cell. Biol. 14, 5278-5289] have previously shown that U1 small nuclear (sn) RNA, both natural or with 5' end mutations, can specifically inhibit reporter gene expression in @entity1 cells. This inhibition occurs when the @entity26798 ' end base pairs near the polyadenylation signal of the reporter gene's pre-mRNA. This base pairing inhibits poly(A) tail addition, a key, nearly universal step in mRNA biosynthesis, resulting in degradation of the mRNA. Here we demonstrate that expression of endogenous @entity1 genes can be efficiently inhibited by transiently or stably expressed 5' end-mutated @entity26798 . Also, we determine the inhibitory mechanism and establish a set of rules to use this technique and to improve the efficiency of inhibition. Two U1 snRNAs base paired to a single pre-mRNA act synergistically, resulting in up to 700-fold inhibition of the expression of specific reporter genes and 25-fold inhibition of endogenous genes. Surprisingly, distance from the @entity26798 binding site to the poly(A) signal is not critical for inhibition, instead the @entity26798 must be targeted to the terminal exon of the pre-mRNA. This could reflect a disruption by the 5' end-mutated @entity26798 of the definition of the terminal exon as described by the exon definition model.

Inhibiting expression of specific genes in XXXX cells with 5' end-mutated U1 small nuclear RNAs targeted to terminal exons of pre-mRNA.

@entity1 :: ('9606', 'Species') :: ['mammalian'] @entity26798 :: ('26871', 'Gene') :: ['U1 snRNA', 'U1 snRNA 5']
@entity1 :: (9606,Species) :: ['mammalian']
