Antagonistic effects of arginine methylation of LSM4 on alternative splicing during plant stress responses

Agrofoglio YC, Iglesias MJ, Perez-Santángelo S, et al. Antagonistic effects of arginine methylation of LSM4 on alternative splicing during plant stress responses. bioRxiv. 2023.**Abstract** Arabidopsis PROTEIN ARGININE METHYLTRANSFERASE 5 (PRMT5) post-translationally modifies RNA-binding proteins by arginine (R) methylation. The impact of this modification on the regulation of RNA processing is largely unknown. Here we use LSM4, a component of the spliceosome, as a paradigm to study the impact of R-methylation on its function in RNA processing. We identify in vivo targets of LSM4 and show that LSM4 regulates alternative splicing of a suite of them. Furthermore, LSM4 affects mRNA levels of some of the targets, showing for the first time its role in both AS and steady-state abundance. Thelsm4andprmt5mutants show a considerable overlap of genes with altered splicing patterns, suggesting that these might be regulated by PRMT5-dependent LSM4 methylation. Wild-type LSM4 and an unmethylable version complement thelsm4-1growth and circadian rhythms defects, suggesting that methylation is not critical for growth in normal environments. However, LSM4 methylation increases with ABA and is necessary for plants to respond properly to salt stress. In contrast, LSM4 methylation is reduced by bacterial infection, and plants expressing unmethylable LSM4 are more resistant than plants expressing wild-type LSM4. This tolerance correlates with decreased intron retention of immune-response genes upon infection, augmenting the functional isoform. Taken together, this provides the first direct evidence that R methylation adjusts LSM4 function on pre-mRNA splicing in an antagonistic manner in response to biotic and abiotic stress. **Highlight**Please provide a statement that, in fewer than 30 words, highlights the novelty of the paper for the non-expert. Arginine methylation of the LSM4 spliceosome component by PROTEIN ARGININE METHYLTRANSFERASE 5 fine-tunes alternative splicing of a set of stress-related genes to antagonistically control biotic and abiotic responses in Arabidopsis. </p

The spliceosome assembly factor GEMIN2 attenuates the effects of temperature on alternative splicing and circadian rhythms

The mechanisms by which poikilothermic organisms ensure that biological processes are robust to temperature changes are largely unknown. Temperature compensation, the ability of circadian rhythms to maintain a relatively constant period over the broad range of temperatures resulting from seasonal fluctuations in environmental conditions, is a defining property of circadian networks. Temperature affects the alternative splicing (AS) of several clock genes in fungi, plants, and flies, but the splicing factors that modulate these effects to ensure clock accuracy throughout the year remain to be identified. Here we show that GEMIN2, a spliceosomal small nuclear ribonucleoprotein assembly factor conserved from yeast to humans, modulates low temperature effects on a large subset of pre-mRNA splicing events. In particular, GEMIN2 controls the AS of several clock genes and attenuates the effects of temperature on the circadian period in Arabidopsis thaliana. We conclude that GEMIN2 is a key component of a posttranscriptional regulatory mechanism that ensures the appropriate acclimation of plants to daily and seasonal changes in temperature conditions.Fil: Schlaen, Rubén Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquimicas de Buenos Aires; Argentina. Fundación Instituto Leloir; ArgentinaFil: Mancini, Estefania. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquimicas de Buenos Aires; ArgentinaFil: Sanchez, Sabrina Elena. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquimicas de Buenos Aires; ArgentinaFil: Perez Santangelo, Maria Soledad. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquimicas de Buenos Aires; ArgentinaFil: Rugnone, Matias Leandro. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquimicas de Buenos Aires; ArgentinaFil: Simpson, Craig G.. James Hutton Institute; Reino UnidoFil: Brown, John W. S.. James Hutton Institute; Reino Unido. University of Dundee at James Hutton Institute; Reino UnidoFil: Zhang, Xu. University of Illinois at Chicago; Estados UnidosFil: Chernomoretz, Ariel. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquimicas de Buenos Aires; ArgentinaFil: Yanovsky, Marcelo Javier. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquimicas de Buenos Aires; Argentin