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Heterochromatin formation in bistable chromatin domains controls the epigenetic repression of clonally variant Plasmodium falciparum genes linked to erythrocyte invasion. | LitMetric

AI Article Synopsis

  • - Clonally variant gene expression allows the malaria parasite Plasmodium falciparum to survive by altering genes related to erythrocyte invasion, particularly within the clag and eba gene families.
  • - This study analyzed the promoters of specific genes (clag3.1, clag3.2, eba-140) and found that gene activity is influenced by the chromatin state and certain histone modifications, specifically H3K9me3 for repression and H3K9ac for activation.
  • - The gene eba-140 exists in two distinct chromatin domains that help regulate its expression, with one domain controlling its activity and the other being associated with a neighboring gene that also exhibits variant

Article Abstract

Clonally variant gene expression is a common survival strategy used by many pathogens, including the malaria parasite Plasmodium falciparum. Among the genes that show variant expression in this parasite are several members of small gene families linked to erythrocyte invasion, including the clag and eba families. The active or repressed state of these genes is clonally transmitted by epigenetic mechanisms. Here we characterized the promoters of clag3.1, clag3.2 and eba-140, and compared nuclease accessibility and post-translational histone modifications between their active and repressed states. Activity of these promoters in an episomal context is similar between parasite subclones characterized by different patterns of expression of the endogenous genes. Variant expression is controlled by the euchromatic or heterochromatic state of bistable chromatin domains. Repression is mediated by H3K9me3-based heterochromatin, whereas the active state is characterized by H3K9ac. These marks are maintained throughout the asexual blood cycle to transmit the epigenetic memory. Furthermore, eba-140 is organized in two distinct chromatin domains, probably separated by a barrier insulator located within its ORF. The 5' chromatin domain controls expression of the gene, whereas the 3' domain shares the chromatin conformation with the upstream region of the neighbouring phista family gene, which also shows variant expression.

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Source
http://dx.doi.org/10.1111/j.1365-2958.2011.07574.xDOI Listing

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