Biology subjects

Waddell, B. M.

Publications and source records attributed to Waddell, B. M..

3 recordsLinked to original sources

bioRxiv2026

Discovery of a small peptide that activates both APCCdc20 and APCCdh1 in yeast, driving increased lifespan

Aging is accompanied by molecular hallmarks conserved from yeast to humans. One such hallmark, senescence, is an irreversible nondividing state that promotes aging. We previously reported that mutants of the yeast Anaphase Promoting Complex (APC) shorten the lifespan of both dividing and nondividing cells. Here, we propose that activation of the APC will promote the maintenance of quiescent yeast cells, thereby delaying senescence and aging. We observed that APC activity in aging quiescent cells becomes increasingly impaired, as the APC substrates Clb1 and Mps1 accumulated within aging cells reintroduced back into the cell cycle. To identify peptide activators of the APC, we used a yeast 2-hybrid screen to recover peptides that interacted with the APC subunit Apc10. Recovered peptides were tested for their effects on the replicative lifespan (RLS) of dividing cells, and the chronological lifespan (CLS) of nondividing cells. Several peptides increased the RLS of wild type cells, but only one peptide (C43-4) increased CLS, which requires the APC Cdh1 co-activator, but not the Cdc20 co-activator. In cells expressing C43-4, Clb1 and Mps1 levels remained low when aging quiescent cells were reintroduced back into the cell cycle. The addition of a synthetic C43-4 to aging quiescent cells increased CLS even when added at late stages of aging. Mutations to APC subunits and co-activators blocked the ability of C43-4 to extend CLS. Htz1, which shares sequence homology with C43-4, was found to suppress APC mutant phenotypes and stabilize Apc10. We individually mutated the 6 amino acids in C43-4 that were shared with Htz1; one of the mutants disrupted the C43-4-Apc10 2-hybrid interaction and abolished the C43-4-dependent increase in CLS. C43-4 action is evolutionarily conserved, as C43-4 increased C. elegans lifespan in a daf-16- and aak-2-dependent manner. Our results describe the discovery of an evolutionarily conserved translational peptide that is the first of its kind to specifically activate the anti-aging APCCdh1 complex.

genetics↗

bioRxiv2023

A role for the C. elegans Argonaute protein CSR-1b isoform in small nuclear RNA 3' processing

The Integrator is a multi-subunit protein complex that catalyzes the maturation of snRNA transcripts via 3 cleavage, a step required for snRNA incorporation with snRNP for spliceosome biogenesis. Here we developed a GFP based in vivo snRNA misprocessing reporter as a readout of Integrator function and performed a genome-wide RNAi screen for Integrator regulators. We found that loss of the Argonaute encoding csr-1 gene resulted in widespread 3 misprocessing of snRNA transcripts that is accompanied by a significant increase in alternative splicing. Loss of csr-1 down-regulates the germline expression of Integrator subunit-4 and is accompanied by a reduced protein translation efficiency of multiple Integrator catalytic and non-catalytic subunits. Through isoform analysis, we identify that csr-1b is specifically required for snRNA processing and this is dependent on its catalytic slicer activity. Moreover, mRNA-sequencing revealed high similarity in the transcriptome profile between csr-1 and Integrator subunit knockdown via RNAi. Together, our findings reveal csr-1b as a new regulator of the Integrator complex and implicate a novel role of this Argonaute protein in snRNA 3 processing.

genetics↗

bioRxiv2022

CCR4-NOT subunit CCF-1/CNOT7 interacts with the PAL-1/CDX-1 transcription factor to regulate multiple stress responses in Caenorhabditis elegans

CCR4-NOT is a versatile eukaryotic protein complex that controls multiple steps in gene expression regulation from synthesis to decay. In yeast, CCR4-NOT has been implicated in stress response regulation, though this function in other organisms remains unclear. In a genome-wide RNAi screen, we identified a subunit of the CCR4-NOT complex, ccf-1, as a requirement for the C. elegans transcriptional response to cadmium and acrylamide stress. Using whole-transcriptome RNA sequencing, we show that knockdown of ccf-1 attenuates the activation of a broad range of stress protective genes in response to cadmium and acrylamide, including those encoding heat shock proteins and glutathione s-transferases. Consistently, survival assays show that knockdown of ccf-1 decreases C. elegans stress resistance. A yeast-2-hybrid screen using a CCF-1 bait identified the homeobox transcription factor PAL-1 as a physical interactor. Knockdown of pal-1 inhibits the activation of ccf-1 dependent stress genes and reduces C. elegans stress resistance. Gene expression analysis reveals that knockdown of pal-1 down-regulates the mRNA levels of elt-2 and elt-3, which serves as the master transcriptional co-regulators of stress response in the C. elegans intestinal and epidermal tissues respectively. These results reveal a new role for CCR4-NOT in stress response regulation with PAL-1 through the transcriptional control of elt-2 and elt-3 in C. elegans.

genetics↗