Mazzoni Cristina, Mancini Patrizia, Madeo Frank, Palermo Vanessa, Falcone Claudio
Department of Cell and Developmental Biology, University of Rome La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy.
FEMS Yeast Res. 2003 Oct;4(1):29-35. doi: 10.1016/S1567-1356(03)00151-X.
We report the study of Kluyveromyces lactis cells expressing a truncated form of KlLSM4, a gene ortholog to LSM4 of Saccharomyces cerevisiae which encodes an essential protein involved in both pre-mRNA splicing and mRNA decapping. We had previously demonstrated that the first 72 amino acids of the K. lactis Lsm4p (KlLsm4Deltap) can restore cell growth in both K. lactis and S. cerevisiae cells not expressing the endogenous protein. However, cells showed a remarkable loss of viability in stationary phase. Here we report that cells expressing KlLsm4Deltap presented clear apoptotic markers such as chromatin condensation, DNA fragmentation, accumulation of reactive oxygen species, and showed increased sensitivity to different drugs. RNA analysis revealed that pre-mRNA splicing was almost normal while mRNA degradation was significantly delayed, pointing to this as the possible step responsible for the observed phenotypes.
我们报告了对表达截短形式的KlLSM4的乳酸克鲁维酵母细胞的研究，KlLSM4是酿酒酵母LSM4的直系同源基因，编码一种参与前体mRNA剪接和mRNA脱帽的必需蛋白质。我们之前已经证明，乳酸克鲁维酵母Lsm4p（KlLsm4Deltap）的前72个氨基酸可以在不表达内源性蛋白质的乳酸克鲁维酵母和酿酒酵母细胞中恢复细胞生长。然而，细胞在稳定期表现出明显的活力丧失。在此我们报告，表达KlLsm4Deltap的细胞呈现出明显的凋亡标志物，如染色质浓缩、DNA片段化、活性氧积累，并对不同药物表现出更高的敏感性。RNA分析表明，前体mRNA剪接几乎正常，而mRNA降解明显延迟，表明这可能是导致观察到的表型的步骤。
