Suppression of the mRNA decay phenotype of the lsm1-27 mutant (C-terminal truncation mutant of LSM1) in trans by the various mutant versions of the C-terminal extension peptide, upon over expression.

RNA isolated from lsm1-27 cells expressing wild type or various mutant versions of the C-terminal extension peptide of Lsm1 from multi copy 2μ vectors were subjected to Northern analysis to reveal the MFA2pG mRNA and the poly(G) fragments. The fractional contribution of the poly(G) fragments to the total signal (total = full-length mRNA + trimmed and normal poly(G) fragments) was approximated for each sample via quantitation using the phosphorimager and normalized to the value obtained for lsm1-27 cells expressing wild type C-terminal extension peptide. Samples with approximate poly(G) fragment levels that are ≥ 80%, 60% to 80% and <60% of the value for cells expressing wild type peptide are marked with +++, ++ and + below the corresponding lanes in the figure.