Yichen Li | Search PubMed

PubMed2026

Duplication-based genetic dissection of the Down syndrome critical region reveals its complex functional organization.

Down syndrome (DS), associated with trisomy 21, is the most common genetic cause of developmental delay and intellectual disability, yet the specific dosage-sensitive genes and the associated genetic mechanisms underlying these phenotypes remain incompletely defined. Here, we applied an additive genetic strategy to dissect the Down syndrome critical region (DSCR) by generating 2 complementary mouse models using Cre/loxP-mediated chromosome engineering that together span the entire DSCR on mouse chromosome 16: Dp(16)5Yey, duplicating the Setd4-Kcnj6 interval, and Dp(16)6Yey, duplicating the Kcnj15-Mx2 interval. In addition, we engineered a third duplication model, Dp(16)7Yey, carrying a selective duplication of the Dyrk1a-Kcnj6 interval containing only these 2 genes. Building upon our previously reported results, cognitive behavioral analyses of these 3 models reveal a complex functional genetic architecture of the DSCR, including dosage-sensitive genetic elements, interactions among these elements, and their contributions to DS-associated cognitive deficits. Together, these findings highlight the complexity of dosage-dependent genetic interactions, which provide important insights into DSCR functional organization and have major implications for the development of effective therapeutic strategies for DS-associated cognitive deficits. In addition, these duplication mouse models represent valuable resources for further genetic dissection of DS phenotypes beyond cognition.

Animals↗

PubMed2026

Biocontrol potential and molecular basis of predation in a marine raptorial ciliate.

Predator-prey interactions are widespread across organisms and are key drivers of morphological and behavioral evolution. Despite this, predation remains poorly understood among microbial eukaryotes, mostly due to the absence of a tractable experimental system that allows quantitative, reproducible investigation. This study establishes the marine raptorial ciliate Chaenea vorax as a highly efficient predator, with Rosenzweig-MacArthur model simulations based on predation data showing that only a few dozen individuals can eliminate the vast majority of the facultatively pathogenic ciliate Uronema marinum within 1-2 days, providing a quantitative basis for developing predator-based biocontrol strategies in aquaculture. Genomic analysis shows that C. vorax possesses a highly fragmented macronuclear genome enriched with predation-related pathways, including calcium-mediated contractility, cellular proteolysis, toxin expulsion systems, among others. Transcriptomic profiling during predation events further demonstrates significant upregulation of genes involved in cytoskeletal remodeling, proteolytic activity, and cellular detoxification. Evolutionary analyses suggest that C. vorax has an extremely long evolutionary history, exceptionally high nucleotide diversity even among ciliates, and gene family expansions linked to predatory adaptation. Although the prey possesses certain defensive mechanisms (e.g. trichocysts), these are largely ineffective against short-term predation in closed aquatic environments. These findings provide fundamental insights into the molecular basis of predation in ciliates and suggest the potential utility of C. vorax in biocontrol applications targeting pathogenic ciliates.

Ciliophora↗