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Histone variant H2B.Z acetylation is necessary for maintenance of Toxoplasma gondii biological fitness. | LitMetric

Histone variant H2B.Z acetylation is necessary for maintenance of Toxoplasma gondii biological fitness.

Biochim Biophys Acta Gene Regul Mech

Laboratorio de Parasitología Molecular, INTECH, CONICET-UNSAM, Av. Intendente Marino Km. 8.2, C.C 164, B7130IIWA, Chascomús, Prov. Buenos Aires, Argentina. Electronic address:

Published: September 2023

AI Article Synopsis

  • * The parasite Toxoplasma gondii has a unique variant of histone H2B called H2B.Z, which, when mutated, affects the parasite's growth, virulence, and response to DNA damage—especially notable in the c-Myc-R mutant.
  • * Mutations to the N-terminal lysines in H2B.Z revealed that acetylation impacts protein interactions and gene expression, linking histone modification to chromosome stability and the cell cycle in T. gondii.

Article Abstract

Through regulation of DNA packaging, histone proteins are fundamental to a wide array of biological processes. A variety of post-translational modifications (PTMs), including acetylation, constitute a proposed histone code that is interpreted by "reader" proteins to modulate chromatin structure. Canonical histones can be replaced with variant versions that add an additional layer of regulatory complexity. The protozoan parasite Toxoplasma gondii is unique among eukaryotes in possessing a novel variant of H2B designated H2B.Z. The combination of PTMs and the use of histone variants are important for gene regulation in T. gondii, offering new targets for drug development. In this work, T. gondii parasites were generated in which the 5 N-terminal acetylatable lysines in H2B.Z were mutated to either alanine (c-Myc-A) or arginine (c-Myc-R). The c-Myc-A mutant displayed no phenotype over than a mild defect in its ability to kill mice. The c-Myc-R mutant presented an impaired ability to grow and an increase in differentiation to latent bradyzoites. The c-Myc-R mutant was also more sensitive to DNA damage, displayed no virulence in mice, and provided protective immunity against future infection. While nucleosome composition was unaltered, key genes were abnormally expressed during in vitro bradyzoite differentiation. Our results show that regulation of the N-terminal positive charge patch of H2B.Z is important for these processes. We also show that acetylated N-terminal H2B.Z interacts with some unique proteins compared to its unacetylated counterpart; the acetylated peptide pulled down proteins associated with chromosome maintenance/segregation and cell cycle, suggesting a link between H2B.Z acetylation status and mitosis.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10524646PMC
http://dx.doi.org/10.1016/j.bbagrm.2023.194943DOI Listing

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