Biology subjects

Silva-Garcia, C. G.

Publications and source records attributed to Silva-Garcia, C. G..

6 recordsLinked to original sources

bioRxiv2026

A simplified intermittent fasting regimen robustly extends C. elegans lifespan without FUdR or antibiotic confounds

Fasting-based dietary interventions are conserved regulators of aging that extend lifespan across species, including Caenorhabditis elegans. However, fasting studies in C. elegans are sensitive to experimental variables that can independently influence lifespan and health, including FUdR, antibiotic treatment, germline-less mutants, and the use of UV- or heat-killed bacteria. FUdR can alter lifespan, age-associated pathology, and stress responses, while antibiotics used to prevent bacterial growth during fasting may directly affect worm physiology. To minimize these confounding factors, we developed a simple adult-onset intermittent fasting paradigm that does not require FUdR, antibiotics, or bacterial killing. Wild-type worms were subjected to daily fasting periods of 5 h, 6 h, or 18 h until day 10 of adulthood and compared with continuously fed controls. Daily intermittent fasting robustly extended lifespan by 24-57%, demonstrating that repeated fasting windows during adulthood are sufficient to promote longevity under minimally confounded conditions. These findings establish a straightforward and experimentally tractable intermittent fasting paradigm for C. elegans and underscore the importance of limiting pharmacological and microbial conditions in dietary-intervention experiments.

physiology↗

bioRxiv2024

Universal Single Copy Knock-In System in Caenorhabditis elegans: One Plasmid to Target All Chromosomes

Successful transgenesis in model organisms has dramatically helped us understand gene function, regulation, genetic networks, and potential applications. Here, we introduce the universal single-copy knock-in system (Universal SKI System or U-SKI), designed for inserting any transgene by CRISPR/Cas9 in the Caenorhabditis elegans genome. The Universal SKI System takes advantage of a plasmid (pSKI), which can also be used for extrachromosomal arrays, to facilitate the insertion of a transgene at specific safe harbor loci on each autosomal chromosome. The pSKI plasmid contains multiple restriction sites for easy cloning and serves as a CRISPR/Cas9-based insertion repair template because it has two synthetic and long homology arms that recombine with the SKI cassettes. This system also uses a single crRNA guide, which acts as a Co-CRISPR enrichment marker. Overall, the Universal SKI System is highly flexible; with the same Universal SKI cassette on each autosome, researchers can select the insertion site and streamline tracking while reducing the complexity of expressing single-copy transgenes in C. elegans.

genetics↗

bioRxiv2022

GRAS-1 is a conserved novel regulator of early meiotic chromosome dynamics in C. elegans

Chromosome movements and licensing of synapsis must be tightly regulated during early meiosis to ensure accurate chromosome segregation and avoid aneuploidy, although how these steps are coordinated is not fully understood. Here we show that GRAS-1, the worm homolog of mammalian GRASP/Tamalin and CYTIP, coordinates early meiotic events with cytoskeletal forces outside the nucleus. GRAS-1 localizes close to the nuclear envelope (NE) in early prophase I and interacts with NE and cytoskeleton proteins. Delayed homologous chromosome pairing, synaptonemal complex (SC) assembly, and DNA double-strand break repair progression are partially rescued by the expression of human CYTIP in gras-1 mutants, supporting functional conservation. However, Tamalin, Cytip double knockout mice do not exhibit obvious fertility or meiotic defects, suggesting evolutionary differences between mammals. gras-1 mutants show accelerated chromosome movement during early prophase I, implicating GRAS-1 in regulating chromosome dynamics. GRAS-1-mediated regulation of chromosome movement is DHC-1-dependent, placing it acting within the LINC-controlled pathway, and depends on GRAS-1 phosphorylation at a C-terminal S/T cluster. We propose that GRAS-1 serves as a scaffold for a multi-protein complex coordinating the early steps of homology search and licensing of SC assembly by regulating the pace of chromosome movement in early prophase I.

cell biology↗

bioRxiv2022

CRTC-1 Balances Histone Trimethylation and Acetylation to Promote Longevity

Loss of function during ageing is accompanied by transcriptional drift, altering gene expression and contributing to a variety of age-related diseases. CREB-regulated transcriptional coactivators (CRTCs) have emerged as key regulators of gene expression that might be targeted to promote longevity. Here, we define the role of the Caenorhabditis elegans CRTC-1 in the epigenetic regulation of longevity. Endogenous CRTC-1 binds chromatin factors, including components of the COMPASS complex, which trimethylates lysine 4 on histone H3 (H3K4me3). CRISPR editing of endogenous CRTC-1 reveals that the CREB-binding domain in neurons is specifically required for H3K4me3-dependent longevity. However, this effect is independent of CREB but instead acts via the transcription factor AP-1. Strikingly, CRTC-1 also mediates global histone acetylation levels, and this acetylation is essential for H3K4me3-dependent longevity. Indeed, overexpression of an acetyltransferase enzyme is sufficient to promote longevity in wild-type worms. CRTCs, therefore, link energetics to longevity by critically fine-tuning histone acetylation and methylation to promote healthy ageing.

genetics↗

bioRxiv2022

Confirming the Pro-longevity Effects of H3K4me3-deficient set-2 Mutants in Extending Lifespan in C. elegans

The COMPASS chromatin complex, which trimethylates lysine 4 on histone H3 (H3K4me3), regulates lifespan in Caenorhabditis elegans. Knockdown or partial loss-of-function of SET-2, a member of the COMPASS complex, extends the lifespan of worms. However, recent observations suggested that full loss of SET-2 methyltransferase activity via deletion of its active site reduces lifespan, indicating the degree of COMPASS inhibition may be critical to its effects on aging. To further explore these inconsistencies, we examined set-2 longevity across a range of interventions from weak to full inhibition. Via CRISPR/Cas9 genome-editing, we made two new set-2 mutants, a new genocopy of the most commonly used set-2(ok952) allele for mild set-2 inhibition, and a full set-2 genomic deletion. We found that both new strains (partial and null) and RNAi show a lifespan extension in C. elegans fed HT115 E. coli. However, neither mutant was long-lived in C. elegans fed OP50-1 E. coli. These data confirm that the previous lifespan extension observed in set-2(ok952) mutants was indeed the result of set-2 inhibition (and not a secondary linked mutation generated in the original strain). These data also indicate that a diet-dependent mechanism might contribute to the regulation of lifespan under H3K4me3 deficiency and highlight how COMPASS-mediated longevity involves a complex interaction between chromatin state and environment.

genetics↗

bioRxiv2018

Single-copy Knock-In Loci for Defined Gene Expression in C. elegans

We have generated a single-copy knock-in loci for defined gene expression (SKI LODGE) system to insert any cDNA by CRISPR/Cas9 at defined safe harbors in the Caenorhabditis elegans genome. Utilizing a single crRNA guide, which also acts as a Co-CRISPR enrichment marker, any cDNA sequence can be introduced as a single integrated copy, regulated by different tissue-specific promoters. The SKI LODGE system provides a fast, economical and effective approach for generating single-copy non-silenced transgenes in C. elegans.

genetics↗