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Leger-Abraham, M.

Publications and source records attributed to Leger-Abraham, M..

2 recordsLinked to original sources

A MultiOmics time-resolved systems map of gene regulation in Toxoplasma gondii

Understanding how T. gondii builds an invasion-competent cell has been limited by its rapid, asynchronous division cycle, incomplete gene function annotation, and studies that have examined one regulator or complex at a time. Here, we placed acute perturbation of 21 transcriptional and epigenetic factors, promoter occupancy, chromatin accessibility, and molecular validation on a common single-cell clock. The resulting consensus map links the lytic-cycle programs to candidate activating and repressive inputs, organizes genes into 108 co-regulated communities, and nominates regulatory partnerships that would not have emerged from any single data type. The work bridges three longstanding gaps: it resolves perturbation responses in cell-cycle time, distinguishes promoter occupancy from perturbation-linked regulation, and turns a large multidimensional dataset into an experimentally navigable map. We indeed confirmed known factor interactions such as MORC/HDAC3 and recovered combinations such as the Cdc5/SNIP1 and DMAP1/EPL1 as coregulatory nodes (that in other systems have been described to cooperate). Furthermore, we discovered a novel apicomplexan specific combination of AAF1/AP2XI-5 that provides mechanistic insights of the unique AP2 transcription factor family.

microbiology↗

Ribosomal Architecture and rRNA Modification Landscape in the Tick-Borne Parasite Babesia divergens

Babesia is a tick-borne intracellular apicomplexan parasite responsible for diseases ranging from mild to fatal, with a broadening geographic distribution. Due to the complex life cycle of Babesia species, their survival depends on the precise control of gene expression, which is primarily regulated by epigenetic, transcriptional, and post-transcriptional mechanisms. High-resolution structural information on key components of the translation machinery, such as ribosomes, could aid in the development of antiparasitic drugs. Here, we report cryo-EM ribosome structures (2.6 [A]) from the tick-borne apicomplexan pathogen Babesia divergens, showing associated tRNAs, an mRNA fragment, and RACK1, a signaling scaffold crucial to translation regulation. Density map analysis displays ribosome regions at atomic resolution (1.7 [A]), which, when combined with nanopore sequencing, enabled the comprehensive identification of rRNA modifications, including modifications unreported in other organisms. The new rRNA modifications localize not only to the reduced Babesia rRNA expansion segments but also to functionally essential ribosomal sites, uncovering new avenues for therapeutic intervention against babesiosis.

microbiology↗