Biology subjects

Wiegertjes, G. F.

Publications and source records attributed to Wiegertjes, G. F..

3 recordsLinked to original sources

bioRxiv2026

Mapping non-coding functional elements in allotetraploid Cyprinus carpio embryo development reveals subgenome variation of transcription regulation

Common carp (Cyprinus carpio) is an important freshwater species for ornamental and aquaculture purposes, and a key cyprinid model for studying allotetraploidy. Its two chromosomally-separated subgenomes show distinct gene expression profiles, but how their regulatory landscapes control gene expression dynamics during development remains unknown. We generated a regulatory atlas by combining transcriptomes across 12 developmental stages with chromatin accessibility maps, transcription start sites and gene regulation-associated histone post-translational modifications. Subgenome-specific annotation and comparison of 254,276 developmental regulatory elements (PADREs) revealed that regulatory subgenome divergence is most prominent during early development, converging toward the phylotypic period, mirroring expression convergence between subgenomes at the same stages. This dynamic was driven by enhancers, while promoters maintained a more stable subgenome bias, extending the hourglass model of developmental constraint to allotetraploid subgenome regulation. Subgenome-specific enhancers were preferentially retained in subgenome B, whereas subgenome A shifted toward homeologous enhancer activity near the phylotypic stage, indicating directional regulatory divergence between subgenomes. Comparison with zebrafish revealed high concordance with sequence conservation and that subgenome B retained more ancestral cyprinid regulatory elements than subgenome A. This developmental regulatory atlas provides a foundational resource for investigating cis-regulatory evolution following the fourth round of vertebrate genome duplication.

genomics↗

bioRxiv2022

An arginase 2 promoter transgenic illuminates anti-inflammatory signalling in zebrafish

The innate immune response to inflammatory stimuli must be finely balanced to produce an appropriate pro-inflammatory response while allowing a subsequent return to homeostasis. In recent years, in vivo transgenic zebrafish models have shed light on the temporal regulation of the pro-inflammatory innate response to immune challenges. However, until now, there have been no zebrafish transgenic models of anti-inflammatory signalling. We compared existing expression data of arginase genes in zebrafish neutrophils and macrophages, strong candidates for an anti-inflammatory marker, and identified that arginase 2 is the most highly expressed Arginase in zebrafish immune cells. We developed an arginase 2 (arg2) bacterial artificial chromosome (BAC) transgenic line, TgBAC(arg2:eGFP)sh571, driving GFP expression under the control of the arg2 promoter. We show that, under resting conditions, arg2:GFP is expressed in ionocytes, matching the in situ hybridisation pattern. Upon immune challenge by injury, bacterial and fungal insults, arg2:GFP is predominantly expressed in neutrophils at early timepoints post-insult. Later in infections, arg2:GFP is expressed in cells associated with foci of infection (including neutrophils and macrophages), alongside liver expression. Our data indicate that arginase 2 is predominantly expressed in neutrophils after immune challenge and suggest that anti-inflammatory signals coincide with pro-inflammatory signals during early wound and infection responses.

immunology↗

bioRxiv2020

Differential response of macrophages and neutrophils to trypanosome infections in zebrafish: occurrence of foamy macrophages

A tightly regulated innate immune response to trypanosome infections is critical to strike a balance between parasite control and inflammation-associated pathology. In the present study, we make use of the recently established Trypanosoma carassii infection model in larval zebrafish to study the early response of macrophages and neutrophils to trypanosome infections in vivo. We consistently identified high- and low-infected individuals and were able to simultaneously characterize their differential innate response. Not only did macrophage and neutrophil number and distribution differ between the two groups, but also macrophage morphology and activation state. Exclusive to high-infected zebrafish, was the appearance of macrophages rich in lipid droplets, confirmed to be foamy macrophages and characterized by a strong pro-inflammatory profile. Altogether, we provide an in vivo characterization of the differential response of macrophage and neutrophil to trypanosome infection and identify foamy macrophages as potentially associated with an exacerbated immune response and susceptibility to the infection. To our knowledge this is the first report of the occurrence of foamy macrophages during an extracellular trypanosome infection.

microbiology↗