Biology subjects

Bhalodi, J. A.

Publications and source records attributed to Bhalodi, J. A..

2 recordsLinked to original sources

bioRxiv2026

A Matter of Degrees: Latitudinal Variation in the Transcriptional Response to High and Low Temperatures in an Estuarine Cnidarian

Populations of the same species inhabiting distinct geographical regions must meet the requirements of local thermal regimes to survive. While individuals integrate both deeply conserved and genotype-specific transcriptional responses to temperature shifts, unique local requirements may diversify the balance between these two mechanisms in distinct populations. The sea anemone Nematostella vectensis inhabits highly variable estuarine environments across a broad geographic range, providing an excellent system to investigate how local adaptations shape responses to temperature stress. While studies have explored the genotypic and phenotypic diversity among N. vectensis populations, the diversity in transcriptional responses to heat and cold remain poorly understood. We used RNA sequencing to characterize transcriptional programs in N. vectensis from Nova Scotia (NS), Maryland (MD), and Florida (FL) under acute temperature treatments at 10{degrees}C and 38{degrees}C. Individuals exhibited a stronger response at 38{degrees}C than at 10{degrees}C, with NS and MD responses being similar and FL exhibiting a unique response. A core set of genes was differentially expressed across all populations under heat stress, while responses to cold were highly population specific. To evaluate the role of a key transcription factor, heat shock factor (HSF), we analyzed the presence of HSF binding sites (HSEs) in promoters of differentially expressed genes (DEGs). Upregulated genes containing three or more promoter HSEs were strongly induced at 38{degrees}C in MD and FL, but not in NS. To identify the involvement of other transcription factors, we searched for overrepresented motifs in the promoters of the top 100 DEGs at 38{degrees}C, revealing a differential enrichment of motifs across the three populations. Together, these findings suggest that N. vectensis populations utilize diverse transcriptional programs in response to common hot and cold temperatures.

ecology↗

bioRxiv2025

Transcription dynamics and regulation of heat shock protein genes during stress and development in the estuarine cnidarian Nematostella vectensis

Heat shock proteins (HSPs) are conserved molecular chaperones that function in protecting cells from proteotoxic conditions. Most eukaryotes have multiple HSP genes that encode for proteins localizing in the cytoplasm, endoplasmic reticulum (ER), and mitochondria. In marine invertebrates of the phylum Cnidaria, where HSPs are often used as biomarkers of environmental stress, little is known about how particular HSPs vary in copy number, expression, inducibility, and regulation within a species. In this study, we characterized the diversity of the full repertoire of HSP70 and HSP90 genes in an emerging model cnidarian, Nematostella vectensis. We identified five distinct HSP70 and three HSP90 genes, with at least one homolog from each family belonging to the three primary clades based on subcellular localization. Although transcription of none of these HSPs was significantly induced by a temperature change of 10{degrees}C, two cytosolic HSP70s and one cytosolic HSP90 were significantly upregulated with a 20{degrees}C increase in temperature. Most HSPs followed a similar pattern of expression across various developmental stages of N. vectensis, with an increase in expression during the early larval stage followed by a decrease during the juvenile stage. HSPs showed evidence for differential expression in particular cell types, where multiple cytosolic and ER HSPs were highly expressed in neuronal and cnidocyte cell types. Moreover, there were differences in the abundance and sequences of regulatory heat shock element motifs in the putative promoters of N. vectensis HSPs, providing a potential mechanistic basis of functional diversification in response to temperature and development. By characterizing the expression of all HSP70 and HSP90 genes in this cnidarian, we reveal distinct roles of these core genes in the proteostasis response, providing a foundation for future functional studies into the diverse contributions of HSPs to cnidarian life cycle and stress resilience.

physiology↗