Biology subjects

Perez-Alemany, J.

Publications and source records attributed to Perez-Alemany, J..

3 recordsLinked to original sources

bioRxiv2024

Plant BCL-Domain Homologues play a conserved role in SWI/SNF complex stability

The SWItch/Sucrose Non-Fermenting (SWI/SNF) complexes are evolutionarily conserved, ATP-dependent chromatin remodelers crucial for multiple nuclear functions in eukaryotes. Recently, plant BCL-Domain Homolog (BDH) proteins were identified as shared subunits of all plant SWI/SNF complexes, significantly impacting chromatin accessibility and various developmental processes in Arabidopsis. In this study, we performed a comprehensive characterization of bdh mutants, revealing a previously overlooked impact on hypocotyl cell elongation. Through detailed analysis of BDH domains, we identified a plant-specific N-terminal domain that facilitates the interaction between BDH and the rest of the complex. Additionally, we uncovered the critical role of the BDH {beta}-hairpin domain, which is phylogenetically related to metazoan BCL7 SWI/SNF subunits. While phylogenetic analyses did not identify BDH/BCL7 orthologs in fungi, structure prediction modeling demonstrated strong similarities between the SWI/SNF catalytic modules of plants, animals, and fungi, and revealed the yeast Rtt102 protein as a structural homolog of BDH and BCL7. This finding is supported by the ability of Rtt102 to interact with the Arabidopsis catalytic module subunit ARP7 and partially rescue the bdh mutant phenotypes. Further experiments revealed that BDH promotes the stability of the ARP4-ARP7 heterodimer, leading to the partial destabilization of ARP4 in the SWI/SNF complexes. In summary, our study unveils the molecular function of BDH proteins in plant SWI/SNF complexes and suggests that {beta}-hairpin-containing proteins are evolutionarily conserved subunits crucial for ARP heterodimer stability and SWI/SNF activity across eukaryotes.

plant biology↗

bioRxiv2023

Genome-wide evidence of the role of Paf1C in transcription elongation and histone H2B monoubiquitination in Arabidopsis

The evolutionarily conserved Paf1 complex (Paf1C) participates in transcription, and research in animals and fungi suggests that it facilitates RNAPII progression through chromatin remodeling. To obtain evidence that Paf1C acts in transcription elongation in Arabidopsis, we examined the genomic distribution of the ELF7 and VIP3 subunits of Paf1C. The occupancy of both subunits was confined to thousands of gene bodies and positively correlated with RNAPII occupancy and the level of gene expression, supporting a role as a transcription elongation factor. We found that monoubiquitinated histone H2B, which marks most transcribed genes, was strongly reduced genome-wide in elf7 seedlings. Genome-wide profiling of RNAPII revealed that in elf7 mutants, RNAPII occupancy was reduced throughout the gene body and at the transcription end site of Paf1C-targeted genes, suggesting a direct role for the complex in transcription elongation. Overall, our observations suggest that there is a direct functional link between Paf1C activity, mono-ubiquitination of histone H2B, and the transition of RNPII to productive elongation. However, for several genes, Paf1C may also act independently of H2Bub deposition or occupy these genes more stably than H2Bub marking, possibly reflecting the dynamic nature of Paf1C association and H2Bub turnover during transcription.

plant biology↗

bioRxiv2022

The TRIPLE PHD FINGERS proteins are required for SWI/SNF complex-mediated +1 nucleosome positioning and 5' transcript length determination in Arabidopsis.

Eukaryotes have evolved multiple ATP-dependent chromatin remodelers to shape the nucleosome landscape. We recently uncovered an evolutionarily conserved SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeler complex in plants reminiscent of the mammalian BAF subclass, which specifically incorporates the MINUSCULE (MINU) catalytic subunits and the TRIPLE PHD FINGERS (TPF) signature subunits. Here we report experimental evidence that establishes the functional relevance of TPF proteins for the complex activity. Our results show that depletion of TPF triggers similar pleiotropic phenotypes and molecular defects to those found in minu mutants. Moreover, we report the genomic location of MINU2 and TPF proteins as representative members of the plant BAF-like complex and their impact on nucleosome positioning and transcription. These analyses unravel the binding of the complex to thousands of genes where it modulates the position of the +1 nucleosome. These targets tend to produce 5-shifted transcripts in the tpf and minu mutants pointing to the participation of the complex in alternative transcriptional start site usage. Interestingly, there is a remarkable correlation between +1 nucleosome shift and 5 transcript length change suggesting their functional connection. In summary, this study unravels the function of a plant SWI/SNF complex involved in +1 nucleosome positioning and 5 transcript length determination.

molecular biology↗