Roles and transcriptional regulation of the endogenous cellulases in association with substrate and cellular processes in a thermoacidophilic archaeon

Li, S.; Huang, Q.; Yang, Y.; Pengju, W.; Li, J.; Shen, Y.; Ni, J.

doi:10.1101/2025.03.28.645846

Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.03.28.645846

Roles and transcriptional regulation of the endogenous cellulases in association with substrate and cellular processes in a thermoacidophilic archaeon

Li, S.·Huang, Q.·Yang, Y.·Pengju, W.·Li, J.·Shen, Y.·Ni, J.

View original source ↗Export metadata ↓

Abstract

Microbes of the order Sulfolobales are potentially next generation platforms for cellulose degradation and utilization. However, the mechanisms of cellulose degradation and utilization remain unclear. In this study, we analyzed the enzymatic activity, localization, transcriptional regulation, and interplay of three endogenous cellulases Cel1, Cel2A, and LacS, and the association of transcription with cellular processes in the model thermophilic archaeon Saccharolobus islandicus REY15A. Overexpression strains based on a vector developed in this study as well as single and double deletion mutants of the three cellulase genes were constructed and analyzed. We reveal that Cel1 and Cel2A are membrane-associated, and a higher proportion of Cel2A is secreted into the medium than Cel1. The expression of all the three cellulases is induced by carboxymethylcellulose sodium (CMC). Furthermore, we found that the transcriptional levels of cel1, cel2A, and lacS are interdependent and cel1 and cel2A levels apparently increased with lacS deletion and overexpression of an ABC transporter, suggesting of an intracellular oligosaccharide-dependent regulatory mechanism. We showed that a cell cycle transcription factor aCcr1 binds to the promoter of cel1 in vitro. Additionally, we accidentally found that the cellulase genes expression increases in the presence of uracil synthesis pathway and deletion of the cellulase genes facilitates cell growth in CMC-containing medium. This study reveals an ingenious and intricated mechanism for cellulose utilization to adapt to extreme environment in archaea and provide insights for engineering Sulfolobales archaea as biomass-degrading and utilization platforms.

Source connections

Published article ↗

Explore related subjects

microbiology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Li, S., Huang, Q., Yang, Y., Pengju, W., Li, J., Shen, Y., Ni, J.. 2025-03-28. Roles and transcriptional regulation of the endogenous cellulases in association with substrate and cellular processes in a thermoacidophilic archaeon. https://doi.org/10.1101/2025.03.28.645846

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

A population-scale landscape of the subgingival microbiome reveals divergent routes to periodontal dysbiosis

Periodontitis is an archetypical mucosal inflammatory disease in which microbiome dysbiosis at the tooth-epithelial interface interacts with host genetic and behavioral risk factors to drive immune-mediated tissue destruction. Although subgingival microbiome compositional shifts are thought to parallel disease severity, microbiome variation at the population-level and its relationship to periodontal clinical phenotypes and disease-modifying factors remain poorly defined. Here, we use unsupervised manifold learning to map the compositional landscape of the subgingival microbiome in 1,355 adults spanning periodontal health to severe periodontitis. We identified eight latent microbiome states organized along a branching continuum from eubiosis to dysbiosis. An intermediate microbial configuration marked ecological destabilization and bifurcation into two distinct periodontitis-associated dysbiotic trajectories, distinguished by links to gingival inflammation and smoking. Although the microbiome trajectories broadly tracked periodontal destruction, a minority of individuals showed discordant microbiome-clinical phenotypes, with some individuals with periodontitis retaining otherwise eubiotic microbiomes enriched for low-abundance pathobionts, while some cases of health or mild disease had highly dysbiotic communities, suggesting distinct host susceptibility. Together, these findings define a population-scale ecological landscape of the subgingival microbiome, reveal divergent trajectories to periodontal dysbiosis, and highlight heterogeneity in the relationship between microbial community structure and clinical disease expression.

microbiology↗

bioRxiv2026

The iron-binding siderophore enterobactin is required for the response of multi-drug resistant Klebsiella pneumoniae to zinc limitation

To persist during infection Klebsiella pneumoniae must overcome nutrient iron and zinc limitation imposed by the host immune system through a process called nutritional immunity. Secreted small molecule siderophores are a major virulence determinant of Klebsiella pneumoniae pathogenesis and are presumed to overcome nutritional immunity by binding iron for bacterial acquisition. In this work, we set out to identify how a multi-drug resistant K. pneumoniae grows in zinc limited environments. Using unbiased transcriptomics, proteomics, and an arrayed transposon screen, we identified that synthesis and uptake of the siderophore enterobactin is required to allow for growth in low zinc conditions. Iron-specific chelators did not replicate this phenotype and addition of supplemental iron through heme in growth media could not complement severe growth defects of enterobactin mutant K. pneumoniae experiencing zinc limitation. Finally, zinc starvation induced enterobactin production independent of the canonical zinc uptake regulator (Zur) transcription factor suggesting an unidentified regulatory mechanism by which Gram-negative pathogens may respond to zinc stress. Together, these studies expand the role of enterobactin beyond iron regulation and highlight a previously unreported link between iron and zinc homeostasis in Klebsiella pneumoniae.

microbiology↗

bioRxiv2026

A microbiota-derived protease links phage susceptibility to host epithelial responses

Bacteriophages are major ecological drivers of gut microbial ecology, yet whether bacterial mechanisms that determine phage susceptibility have consequences for the mammalian host remains poorly understood. Here, we identify dipeptidyl peptidase 11 (Dpp11a), the predominant active serine protease of the prevalent gut commensal Phocaeicola vulgatus, as an unexpected bacterial defence factor. Dpp11a protects against environmental proteases and confers resistance to bacteriophage infection. Metatranscriptomic analyses further reveal increased expression of both dpp11a and P. vulgatus-associated phage transcripts in ulcerative colitis stool samples, indicating that both components of this interaction are transcriptionally active in disease-associated human microbiomes. Using the microfluidic gut-on-a-chip co-culture model HuMiX, we show that the absence of Dpp11 is accompanied by altered epithelial tight-junction remodelling during phage-bacterial infection. Together, our findings reveal that the consequences of bacterial phage defence can extend beyond phage-bacterium interactions to the mammalian epithelium.

microbiology↗