Biology subjects

Rongo, C.

Publications and source records attributed to Rongo, C..

4 recordsLinked to original sources

bioRxiv2024

Analysis of Categorical Data with Logistic Regression and the Cochran-Mantel-Haenszel Tests in Biological Experiments

The choice of statistical test is a fundamentally important one when analyzing experimental data. Here, we consider the question of categorical data, defined by their properties (for example color) rather than by continuous numbering. Using simple and complex example datasets generated from Caenorhabditis elegans research, we conduct a statistical analysis of (1) a rare cellular event involving the formation of a neuronal extrusion called an exopher, and of (2) a variable behavioral response across a timescale. Two tests we use here are the Cochran- Mantel-Haenszel (CMH) test and logistic regression. These two tests pose practical challenges to researchers that include lack of easy access to statistical software and the need for prior programming knowledge. To this end we provide step-by-step tutorials and example code. We emphasize the flexibility of logistic regression in handling both simple and complex datasets, emphasizing the capacity of logistic regression to provide more comprehensive insights into experimental outcomes than simpler tests like CMH. By analyzing real biological examples and demonstrating their analysis with R code, we provide a practical guide for biologists to enhance the rigor and reproducibility of categorical data analysis in experimental studies.

genetics↗

bioRxiv2024

Genome-wide analysis of Smad and Schnurri transcription factors in C. elegans demonstrates widespread interaction and a function in collagen secretion

Smads and their transcription factor partners mediate the transcriptional responses of target cells to secreted ligands of the Transforming Growth Factor-{beta} (TGF-{beta}) family, including those of the conserved bone morphogenetic protein (BMP) family, yet only a small number of direct target genes have been well characterized. In C. elegans, the BMP2/4 ortholog DBL-1 regulates multiple biological functions, including body size, via a canonical receptor-Smad signaling cascade. Here, we identify functional binding sites for SMA-3/Smad and its transcriptional partner SMA-9/Schnurri based on ChIP-seq peaks (identified by modEncode) and expression differences of nearby genes identified from RNA-seq analysis of corresponding mutants. We found that SMA-3 and SMA-9 have both overlapping and unique target genes. At a genome- wide scale, SMA-3/Smad acts as a transcriptional activator, whereas SMA-9/Schnurri direct targets include both activated and repressed genes. Mutations in sma-9 partially suppress the small body size phenotype of sma-3, suggesting some level of antagonism between these factors and challenging the prevailing model for Schnurri function. Functional analysis of target genes revealed a novel role in body size for genes involved in one-carbon metabolism and in the endoplasmic reticulum (ER) secretory pathway, including the disulfide reductase dpy-11. Our findings indicate that Smads and SMA-9/Schnurri have previously unappreciated complex genetic and genomic regulatory interactions that in turn regulate the secretion of extracellular components like collagen into the cuticle to mediate body size regulation.

genomics↗

bioRxiv2024

NEKL-4 regulates microtubule stability and mitochondrial health in C. elegans ciliated neurons

Ciliopathies are often caused by defects in the ciliary microtubule core. Glutamylation is abundant in cilia, and its dysregulation may contribute to ciliopathies and neurodegeneration. Mutation of the deglutamylase CCP1 causes infantile-onset neurodegeneration. In C. elegans, ccpp-1 loss causes age-related ciliary degradation that is suppressed by mutation in the conserved NEK10 homolog nekl-4. NEKL-4 is absent from cilia, yet negatively regulates ciliary stability via an unknown, glutamylation-independent mechanism. We show that NEKL-4 was mitochondria-associated. nekl-4 mutants had longer mitochondria, a higher baseline mitochondrial oxidation state, and suppressed ccpp-1 mutant lifespan extension in response to oxidative stress. A kinase-dead nekl-4(KD) mutant ectopically localized to ccpp-1 cilia and rescued degenerating microtubule doublet B-tubules. A nondegradable nekl-4(PEST{Delta}) mutant resembled the ccpp-1 mutant with dye filling defects and B-tubule breaks. The nekl-4(PEST{Delta}) Dyf phenotype was suppressed by mutation in the depolymerizing kinesin-8 KLP-13/KIF19A. We conclude that NEKL-4 influences ciliary stability by activating ciliary kinesins and promoting mitochondrial homeostasis. SummaryNeurodegeneration and ciliary degeneration are caused by mutation of the deglutamylase CCP1/CCPP-1 in humans and C. elegans. The conserved NIMA-related kinase NEKL-4/NEK10 can suppress or promote degeneration in an activity-dependent manner that involves cilia-mitochondria communication and that is independent of glutamylation.

cell biology↗

bioRxiv2021

The Hypoxia Response Pathway Promotes PEP Carboxykinase Expression And Gluconeogenesis

Actively dividing cells, including some cancers, rely on aerobic glycolysis rather than oxidative phosphorylation to generate energy, a phenomenon termed "the Warburg effect1." Constitutive activation of the Hypoxia Inducible Factor (HIF-1), a transcription factor known for mediating an adaptive response to oxygen deprivation (hypoxia), is a hallmark of the Warburg effect2. HIF-1 is thought to promote glycolysis and suppress oxidative phosphorylation. Here, we show instead that HIF-1 can promote gluconeogenesis. Using a multiomics approach, we determined the genomic, transcriptomic, and metabolomic landscapes regulated by constitutively active HIF-1 in C. elegans. We performed RNA-seq and ChIP-seq under aerobic conditions in mutants lacking EGL-9, a key negative regulator of HIF-1, and then integrated these approaches to identify over a hundred genes directly and functionally upregulated by HIF-1. We show that HIF-1 directly promotes the expression of PCK-1, a PEP carboxykinase that is a rate-limiting mediator of gluconeogenesis3. This activation of PCK-1 by HIF-1 promotes survival in response to both oxidative and hypoxic stress. Our work is the first to identify functional direct targets of HIF-1 in vivo, and it describes the first complete metabolome induced by constitutive HIF-1 activation in any organism.

genetics↗