title: A critical role of perinuclear filamentous actin in spatial repositioning and mutually exclusive expression of virulence genes in malaria parasites.
abstract: Many microbial pathogens, including the malaria parasite Plasmodium falciparum, vary surface protein expression to evade host immune responses. P. falciparium antigenic variation is linked to var gene family-encoded clonally variant surface protein expression. Mututally exclusive var gene expression is partially controlled by spatial positioning; silent genes are retained at distinct perinuclear sites and relocated to transcriptionally active locations for monoallelic expression. We show that var introns can control this process and that var intron addition relocalizes episomes from a random to a perinuclear position. This var intron-regulated nuclear tethering and repositioning is linked to an 18 bp nuclear protein-binding element that recruits an actin protein complex. Pharmacologically induced F-actin formation, which is restricted to the nuclear periphery, repositions intron-carrying episomes and var genes and disrupts mutually exclusive var gene expression. Thus, actin polymerization relocates var genes from a repressive to an active perinuclear compartment, which is crucial for P. falciparium phenotypic variation and pathogenesis.
authors.affiliation: Institute of Infectious Diseases and Vaccine Development, Tongji University School of Medicine, Shanghai, China.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yufu
authors.initials: Y
authors.lastname: Huang
authors.forename: Yilong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Fang
authors.forename: Aurelie
authors.initials: A
authors.lastname: Claes
authors.forename: Magalie
authors.initials: M
authors.lastname: Duchateau
authors.forename: Abdelkader
authors.initials: A
authors.lastname: Namane
authors.forename: Jose-Juan
authors.initials: JJ
authors.lastname: Lopez-Rubio
authors.forename: Weiqing
authors.initials: W
authors.lastname: Pan
authors.forename: Artur
authors.initials: A
authors.lastname: Scherf
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D007438:Introns; D016778:Malaria, Falciparum / Q000469:parasitology*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D010963:Plasmodium falciparum / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; D015800:Protozoan Proteins; D037521:Virulence Factors; C085731:erythrocyte membrane protein 1, Plasmodium falciparum
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