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Diffendall, G. M.

Publications and source records attributed to Diffendall, G. 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↗

RNA polymerase III is involved in regulating Plasmodium falciparum virulence

While often undetected and untreated, persistent seasonal asymptomatic malaria infections remain a global public health problem. Despite the presence of parasites in the peripheral blood, no symptoms develop. Disease severity is correlated with the levels of infected red blood cells (iRBCs) adhering within blood vessels. Changes in iRBC adhesion capacity have been linked to seasonal asymptomatic malaria infections, however how this is occurring is still unknown. Here we present evidence that RNA polymerase III (RNA Pol III) transcription in Plasmodium falciparum is downregulated in field isolates obtained from asymptomatic individuals during the dry season. Through experiments with in vitro cultured parasites, we have uncovered an RNA Pol III-dependent mechanism that controls pathogen proliferation and expression of a major virulence factor in response to external stimuli. Our findings establish a connection between P. falciparum cytoadhesion and a non-coding RNA family transcribed by Pol III. Additionally, we have identified P. falciparum Maf1 as a pivotal regulator of Pol III transcription, both for maintaining cellular homeostasis and responding adaptively to external signals. These results introduce a novel perspective that contributes to our understanding of P. falciparum virulence. Furthermore, they establish a connection between this regulatory process and the occurrence of seasonal asymptomatic malaria infections.

microbiology↗