Biology subjects

Monzon-Casanova, E.

Publications and source records attributed to Monzon-Casanova, E..

3 recordsLinked to original sources

bioRxiv2022

Polypyrimidine Tract Binding Protein 1 regulates the activation of mouse CD8 T cells

We show that the RNA-binding protein Polypyrimidine Tract Binding Protein 1 (PTBP1) is dispensable for the development of naive mouse CD8 T cells, but is necessary for the optimal expansion and production of effector molecules by antigen-specific CD8 T cells in vivo. PTBP1 has an essential role in regulating the early events following activation of the naive CD8 T cell leading to IL-2 and TNF production. It is also required to protect activated CD8 T cells from apoptosis. PTBP1 controls alternative splicing of over 400 genes in naive CD8 T cells in addition to regulating the abundance of [~]200 mRNAs. PTBP1 is required for the nuclear accumulation of c-Fos, NFATc2 and NFATc3, but not NFATc1. This selective effect on NFAT proteins correlates with PTBP1-promoted expression of the shorter A{beta}1 isoform and exon 13 skipped A{beta}2 isoform of the catalytic A-subunit of calcineurin phosphatase. These findings reveal a crucial role for PTBP1 in regulating CD8 T cell activation.

immunology↗

bioRxiv2021

An improved iCLIP protocol

Crosslinking and Immunoprecipitation (CLIP) is a powerful technique to obtain transcriptome-wide maps of in vivo protein-RNA interactions, which are important to understand the post-transcriptional mechanisms mediated by RNA binding proteins (RBPs). Many variant CLIP protocols have been developed to improve the efficiency and convenience of cDNA library preparation. Here we describe an improved individual nucleotide resolution CLIP protocol (iiCLIP), which can be completed within 4 days from UV crosslinking to libraries for sequencing. For benchmarking, we directly compared PTBP1 iiCLIP libraries with the iCLIP2 protocol produced under standardised conditions, and with public eCLIP and iCLIP PTBP1 data. We visualised enriched motifs surrounding the identified crosslink positions and RNA maps of these crosslinks around the alternative exons regulated by PTBP1. Notably, motif enrichment was higher in iiCLIP and iCLIP2 in comparison to public eCLIP and iCLIP, and we show how this impacts the specificity of RNA maps. In conclusion, iiCLIP is technically convenient and efficient, and enables production of highly specific datasets for identifying RBP binding sites.

molecular biology↗

bioRxiv2019

Polypyrimidine Tract Binding Proteins are essential for B cell development

Polypyrimidine Tract Binding Protein 1 (PTBP1) is a RNA-binding protein (RBP) expressed throughout B cell development. Deletion of Ptbp1 in mouse pro-B cells results in upregulation of PTBP2 and normal B cell development. We show that PTBP2 compensates for PTBP1 in B cell ontogeny as deletion of both Ptbp1 and Ptbp2 results in a complete block at the pro-B cell stage and a lack of mature B cells. In pro-B cells PTBP1 ensures precise synchronisation of the activity of cyclin dependent kinases at distinct stages of the cell cycle, suppresses S-phase entry and promotes progression into mitosis. PTBP1 controls mRNA abundance and alternative splicing of important cell cycle regulators including CYCLIN-D2, c-MYC, p107 and CDC25B. Our results reveal a previously unrecognised mechanism mediated by a RBP that is essential for B cell ontogeny and integrates transcriptional and post-translational determinants of progression through the cell cycle.

immunology↗