Biology subjects

Cussiol, J. R. R.

Publications and source records attributed to Cussiol, J. R. R..

2 recordsLinked to original sources

bioRxiv2024

Functional characterization of N-acetyltransferase 10 (NAT10) in Leishmania mexicana

Leishmania presents a complex life cycle that involves both invertebrate and vertebrate hosts. By regulating gene expression, protein synthesis, and metabolism, the parasite can adapt to various environmental conditions. This regulation occurs mainly at the post-transcriptional level and may involve epitranscriptomic modifications of RNAs. Recent studies have shown that mRNAs in humans undergo a modification known as N4-acetylcytidine (ac4C) catalyzed by the enzyme N-acetyltransferase (NAT10), impacting mRNAs stability and translation. Here, we characterized the NAT10 homologue of L. mexicana, finding that the enzyme exhibits all the conserved acetyltransferase domains and although failed to functionally complement the Kre33 mutant in Saccharomyces cerevisiae, has in vitro acetyltransferase activity. We also discovered that LmexNAT10 is nuclear, and seems essential, as evidenced by unsuccessful attempts to obtain null mutant parasites. Phenotypic characterization of single-knockout parasites revealed that LmexNAT10 affects the multiplication of procyclic forms and the promastigote-amastigote differentiation. Additionally, in vivo infection studies using the invertebrate vector Lutzomyia longipalpis showed a delay in the parasite differentiation into metacyclics. Finally, we observed changes in the cell cycle progression and protein synthesis in the mutant parasites. Together, these results suggest that LmexNAT10 might be important for parasite differentiation, potentially by regulating ac4C levels.

microbiology↗

bioRxiv2022

The transcriptional repressor Opi1 modulates the DNA Damage Response by downregulation of inositol pyrophosphates in Saccharomyces cerevisiae

In budding yeast, the transcriptional repressor Opi1 regulates phospholipid biosynthesis by repressing expression of genes containing inositol-sensitive upstream activation sequences (UASINO). Upon genotoxic stress, cells activate the DNA Damage Response (DDR) to coordinate a complex network of signaling pathways aimed at preserving genomic integrity. Here, we reveal that Opi1 is important to modulate transcription in response to genotoxic stress. We find that cells lacking Opi1 exhibit hypersensitivity to genotoxins, along with a delayed G1 to S-phase transition and decreased gamma-H2A levels. Transcriptome analysis using RNA-seq reveals that Opi1 plays a central role in modulating essential biological processes during genotoxic stress induced by methyl methanesulfonate, including repression of phospholipid biosynthesis and transduction of mating signaling. Moreover, Opi1 induces sulfate assimilation and amino acid metabolic processes, such as arginine and histidine biosynthesis and glycine catabolism. Furthermore, we observe increased mitochondrial DNA instability in opi1{Delta} cells upon MMS treatment. Notably, we show that constitutive activation of the transcription factors Ino2-Ino4 is responsible for genotoxin sensitivity in Opi1-deficient cells, and the production of inositol pyrophosphates by Kcs1 counteracts Opi1 function specifically during MMS-induced genotoxic stress. Overall, our findings highlight Opi1 as a critical sensor of genotoxic stress in budding yeast, orchestrating gene expression to facilitate appropriate DNA damage response.

cell biology↗