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Biology subjects

Mezes, M.

Publications and source records attributed to Mezes, M..

2 recordsLinked to original sources

The Cause of Most Common Antler Abnormality is Not a Fracture But an Osteomyelitis Like Disease the Pedunculitis Chronica Deformans

Climate change is increasing the incidence of certain diseases in wildlife, offering a deeper understanding of their underlying causes. Traditionally, the most common antler abnormalities have been attributed to trauma, based on their morphology. However, this explanation does not account for the epidemic-like spread of abnormalities in specific regions, suggesting that they might be a previously undescribed aspect of this anomaly. In fallow deer (Dama dama), using advanced medical diagnostic tools, we identified an osteomyelitis-like condition, Pedunculitis Chronica Deformans (PCD) which is also observed in other Cervidae. The incidence of this disease shows a strong correlation with the production of mycotoxins by molds that are becoming more prevalent with global warming. Mycotoxins can inhibit wound healing through scar formation after the antlers are cast, leading to the development of PCD. In this report we characterize PCD pathomorphology and introduce a scoring system to differentiate it from other deformities. Moreover, we argue that the most common anomalies such as fractures, antler losses, fatal meningoencephalitis and brain abscesses are complications of PCD. Our research underscores the potential of antlers to serve as biomarkers for mycotoxin exposure.

zoology↗

H3K4 methylation-promoted transcriptional memory ensures faithful zygotic genome activation and embryonic development

In the life of a vertebrate embryo, gene expression is initiated for the first time at zygotic genome activation (ZGA). Maternally expressed transcription factors present in the embryo are essential for this process. However, it is unknown if active chromatin modifications established in the gamete are propagated in the embryo as an epigenetic memory to support ZGA and embryonic development. Here, we provide evidence that in Xenopus laevis, H3K4 methylation provides an epigenetic memory of active chromatin states. We show that this is required for faithful zygotic genome activation and successful embryonic development. Chromatin configurations of promoters displaying high H3K4me3 intensity and breadth, alongside DNA hypomethylation and increased GC content, are propagated from the gametes to the embryo across multiple cell divisions and a transcriptionally quiescent phase in early development. We show that this transmission of H3K4 methylation is essential for precise zygotic genome activation and expression of key pioneer ZGA transcription factors Pou5f3.2 and Sox3. Finally, we demonstrate that the H3K4 methyltransferases Kmt2b and Cxxc1 ensure transcription-independent propagation of H3K4me3 and proper zygotic gene expression. In summary, our study establishes the role of H3K4 methylation in maintaining memory of active chromatin states in Xenopus embryos and reveals its importance for successful embryonic development.

developmental biology↗