Biology subjects

Goretti, D.

Publications and source records attributed to Goretti, D..

3 recordsLinked to original sources

bioRxiv2023

Methylosome and SMN complexes are dispensable for snRNP assembly in Arabidopsis

The role of RNA splicing as modulator of the molecular responses to stress is well described. In contrast, its importance in the acclimation of plants to changes in ambient temperatures started to emerge only recently. Here, we analyzed the role of temperature in spliceosome assembly, a key step often neglected in studies focusing on splicing. Taking advantage of mutants showing temperature-dependent phenotypes we conducted a comprehensive study of the role that the methylosome and SMN complexes have in plant snRNP assembly. Genetic analyses, as well as in vivo and in vitro evidence suggest a mechanism for snRNP assembly in plants that differs remarkably from vertebrate animals. The SMN complex in plants is apparently reduced to a single protein, GEMIN2, that is not essential for plant development. Similarly, the methylosome has a less crucial role in spliceosome assembly than previously thought. Our results highlight how an evolutionary conserved molecular process like RNA splicing has nevertheless evolved plant specific characteristics.

plant biology↗

bioRxiv2023

Temperature-dependent regulation of Arabidopsis thaliana growth and development by LSM7

Temperature affects plant growth by modulating the expression of genes and subsequent processing of RNAs that govern essential physiological processes. Here, we show that Arabidopsis thaliana Sm-like7 (LSM7), a core component of the splicing and decapping machinery, is indispensable for embryogenesis and development. Hypomorphic lsm7-2 mutants display severe developmental defects that are exacerbated by high temperatures. Transcriptome analysis verified LSM7s extensive role in gene regulation. In particular, we found that the key regulator of thermomorphogenesis, PHYTOCHROME INTERACTING FACTOR 4 (PIF4), and auxin-related genes, including SMALL AUXIN UP-REGULATED (SAUR) genes, are misregulated in lsm7-2. Auxin metabolic profiling confirmed that auxin homeostasis was disturbed in lsm7-2. Importantly, overexpression of the auxin-responsive SAUR19 gene partially restored thermomorphogenesis defects in lsm7-2 under high ambient temperature. Taken together, our research provides mechanistic insights into the interplay between RNA processing, hormone homeostasis, and the response to temperature regulation in plants and elucidates LSM7s essential function in plant temperature acclimation and resilience. Significance StatementGiven their sessile nature, plants cannot escape adverse environmental conditions such as cold or heat. Instead, they continuously adjust their gene expression and RNA processing to regulate growth and physiology in response to their surroundings. In this study, we investigated the role of the core RNA processing factor LSM7 in temperature acclimation in Arabidopsis thaliana. We found that LSM7 knockdown mutants were impaired in thermomorphogenesis and, as a result, were hypersensitive to elevated temperatures. At the molecular level, we demonstrated that this temperature sensitivity was caused by the misregulation of key regulators of thermomorphogenesis, including PIF4, auxin homeostasis and signaling, and SAUR genes. Our findings provide valuable insights into the role of RNA processing in plant temperature acclimation.

plant biology↗

bioRxiv2022

PICLN modulates alternative splicing and ensures adaptation to light and temperature changes in plants

Plants undergo transcriptome reprogramming to adapt to daily and seasonal fluctuations in light and temperature conditions. While most efforts have focused on the role of master transcription factors, the importance of splicing factors modulating these processes is now emerging. Efficient pre-mRNA splicing depends on proper spliceosome assembly, which in plants and animals requires the methylosome complex. PICLN is part of the methylosome complex in both humans and Arabidopsis thaliana, and we show here that the human PICLN ortholog rescues phenotypes of A. thaliana picln mutants. Altered photomorphogenic and photoperiodic responses in A. thaliana picln mutants are associated with changes in pre-mRNA splicing, which partially overlap with those in prmt5 mutants. Mammalian PICLN also acts in concert with the Survival Motor Neuron (SMN) complex component GEMIN2 to modulate the late steps of UsnRNP assembly, and many alternative splicing events regulated by PICLN but not PROTEIN-ARGININE METHYL TRANSFERASE 5 (PRMT5), the main protein of the methylosome, are controlled by A. thaliana GEMIN2. As with GEMIN2 and SME1/PCP, low temperature, which increases PICLN expression, aggravates morphological and molecular defects of picln mutants. Taken together, these results establish a key role for PICLN in the regulation of pre-mRNA splicing and in mediating plant adaptation to daily and seasonal fluctuations in environmental conditions.

plant biology↗