Biology subjects

Belisova, D.

Publications and source records attributed to Belisova, D..

3 recordsLinked to original sources

bioRxiv2026

A Myb-dominated gene regulatory network universally controls sexual cell fate transitions in diatoms

Diatoms are the foundation of aquatic food webs and contribute about 40% of the total marine primary productivity. Yet, the regulation of their complex size-dependent life cycles remains obscure. Here, we leveraged single-cell transcriptomics and transgenic reporter lines to uncover the molecular mechanisms behind partner recognition, nuclear fusion, and the remarkable 15-fold size expansion of auxospores. Gene regulatory network inference revealed that the irreversible commitment to differentiate into gametes is controlled by Myb transcription factors, whose specific activity in the global ocean underscores their significance for ploidy transitions across diatom clades. These findings reinforce microalgae as powerful models to study cell fate transitions and provide a mechanistic framework for the life cycle dynamics that underpin the functioning of aquatic systems worldwide. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=67 SRC="FIGDIR/small/714157v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@162f523org.highwire.dtl.DTLVardef@1cbe836org.highwire.dtl.DTLVardef@1fa6c9eorg.highwire.dtl.DTLVardef@1f12217_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2024

FSP1 stem/progenitor cells are essential for TMJ growth and homeostasis

The temporomandibular joint (TMJ) is one of the most used joints in the body. Defects and wear in the cartilage of the joint, condyle, and fibrocartilage disc lie at the heart of many common TMJ disorders. During postnatal development the condyle acts as a growth centre for the mandible with cells moving as a conveyor belt away from the top of the condyle as they differentiate. The superficial layers of the condyle have been proposed to contain stem/progenitor populations to allow growth and maintain homeostasis. Here we have focused on the role of FSP1 (also known as S100a4), as a key fibroblast stem/progenitor marker for the condyle. Lineage tracing using FSP1-Cre;mTmG mice revealed that FSP1-positive cells were restricted to the superficial fibroblast zone giving rise to all layers of the condyle over time. The FSP1-expressing cells overlapped with other putative stem cell markers of the condyle, Gli1 and Scleraxis. BrdU pulse chase experiments highlighted that a subset of FSP1 fibrocartilage were label-retaining, suggesting that FSP1 labels a novel stem/progenitor cell population in the condyle. Destruction of FSP1-expressing cells by conditional diphtheria toxin activity in FSP1-Cre;DTA mice resulted in severe TMJ osteoarthritis (TMJOA) with loss of the cartilage structure. Lgr5 expressing cells in the superficial layer of the condyle, have previously been shown to create a Wnt inhibitory niche. FSP1 expression postnatally was associated with a reduction in canonical Wnt activity in the condyle. Importantly, constitutive activation of Wnt/{beta} catenin in FSP1 cells, led to a downregulation of FSP1 and progressive postnatal loss of TMJ condylar hyaline cartilage due to loss of the superficial stem/progenitor cells. These data demonstrate a novel role for FSP1-expressing cells in the superficial zone in growth and maintenance of the TMJ condylar cartilage and highlight the importance of regulating Wnt activity in this population.

developmental biology↗

bioRxiv2024

Molecular fingerprints of cell size sensing and mating type differentiation in pennate diatoms

O_LIA unique cell size sensing mechanism is at the heart of the life cycle of diatoms. During population growth, cell size decreases until a Sexual Size Threshold (SST) is reached, below which cells become sexually competent. In most pennate diatoms, the two mating types undergo biochemical and behavioral differentiation below the SST, although the molecular pathways underlying their size-dependent maturation remain unknown. C_LIO_LIHere, we developed a method to shorten the generation time of Cylindrotheca closterium through single-cell microsurgery, enabling the transcriptomic comparison of genetically identical large and undifferentiated cells with small, sexually competent cells for six different genotypes. C_LIO_LIWe identified 21 genes upregulated in small cells regardless of their mating type, revealing how cells undergo specific transcriptional reprogramming when passing the SST. Furthermore, we revealed a size-regulated gene cluster with three mating type-specific genes susceptible to sex-inducing pheromones. In addition, comparative transcriptomics confirmed the shared mating type specificity of Mating-type Related Minus 2 homologs in three pennate diatoms, suggesting them to be part of a conserved partner-recognition mechanism. C_LIO_LIThis study sheds light on how diatoms acquire sexual competence in a strictly size-dependent manner, revealing a complex machinery underlying size-dependent maturation, mating behavior, and heterothally in pennate diatoms. C_LI

plant biology↗