Transcriptomic Insights Into the Evolution of Snake Venom: Mechanisms, Diversity, and Adaptation

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  Transcriptomic Insights Into the Evolution of Snake Venom: Mechanisms, Diversity, and Adaptation Abstract Snake venoms are evolutionarily refined biochemical arsenals composed of diverse toxins with complex functional roles in predation, defense, and competition. Over the past 2 decades, transcriptomic approaches have transformed venom research by enabling high-resolution insights into gene expression dynamics, molecular diversity, and the evolutionary mechanisms driving venom variation across lineages. In this review, we present a comprehensive synthesis of snake venom transcriptomics literature and propose a conceptual framework structured around three major axes: (1) gene family expansion through duplication and neofunctionalization; (2) regulatory complexity encompassing transcriptional, posttranscriptional, and epigenetic modulation; and (3) ecological selection pressures shaping venom profiles in response to diet, habitat, and interspecific interactions. We integrate findin...

The protamines of the spider Steatoda sp. provide an example of liquid-liquid phase separation chromatin transitions during spermiogenesis

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The protamines of the spider Steatoda sp. provide an example of liquid-liquid phase separation chromatin transitions during spermiogenesis

While there is extensive information about sperm nuclear basic proteins (SNBP) in vertebrates, there is by comparison, very little information in Arthropoda. This paper aims to contribute to filling this gap by analyzing these proteins in the sperm of the noble false widow spider Steatoda nobilis (Order Araneae, Family Theridiidae). To this end, we have developed a protein extraction method that allows the extraction of both cysteine-containing and non-Cysteine-containing protamines that is suitable for the preparation and analysis of SNBPs from samples where the amount of starting tissue material is limited. We carried out top-down mass spectrometry sequencing and molecular phylogenetic analyses to characterize the protamines of S. nobilis and other spiders. We also used electron microscopy to analyse the chromatin organization of the Steatoda sperm and we found it to exhibit liquid-liquid phase spinodal decomposition during the late stages of spermiogenesis. These studies further our knowledge on the distribution of SNBPs within the animal kingdom and provide additional support for a proposed evolutionary origin of many protamines from a histone H1 (H5) replication independent precursor.

Melissa R. Leyden, Peter Michalik, Luciana Baruffaldi, Susheen Mahmood, Ladan Kalani, Donald F. Hunt, Jose Maria Eirin-Lopez, Maydianne C. B. Andrade, Jeffrey Shabanowitz, Juan Ausió; The protamines of the spider Steatoda sp. provide an example of liquid-liquid phase separation chromatin transitions during spermiogenesis. Development 2024; dev.203134. doi: https://doi.org/10.1242/dev.203134