The missed histone H1 is involved in cell division and ribosome biosynthesis in Toxoplasma gondii

ABSTRACT: Chromatin dynamics can regulate all DNA-dependent processes. Access to DNA within chromatin is orchestrated mainly by histones and their posttranslational modifications (PTM). Like other eukaryotes, the apicomplexan parasite Toxoplasma gondii encodes for four canonical histones and five histone variants. By contrast, the linker histone (H1) has never been identified in apicomplexan parasites. In other eukaryotes, histone H1 compacts the chromatin by linking the nucleosome and increasing the DNA compaction. H1 is a multifunctional protein and can be involved in different steps of DNA metabolism or associated with protein complexes related to distinct biological processes. We have identified a novel protein in T. gondii that, although lacking the globular domain of mammalian H1, is remarkably like the H1-like proteins of bacteria and trypanosomatids. Our results demonstrate that TgH1-like is a nuclear protein associated with chromatin and other histones. Curiously, TgH1-like is also in the nucleolus and associated with ribosomal proteins, indicating a versatile function in this parasite. Although knockout of tgh1-like does not affect the cell cycle, it causes endopolygeny and asynchronous division. Interestingly, mutating post-translationally modified amino acids results in defects in cell division like ∆tgh1-like, showing that these sites are important for protein function. Furthermore, in the bradyzoite stage, this protein is expressed only in dividing parasites, reinforcing its importance in cell division. Indeed, the absence of TgH1-like decreases compaction of peripheral chromatin, confirming its role in the chromatin modulation in T. gondii.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Toxoplasma Gondii Veg

TISSUE(S): Cell Culture

SUBMITTER: Julia Cunha  

LAB HEAD: Sheila Nardelli

PROVIDER: PXD037318 | Pride | 2022-11-30

REPOSITORIES: Pride