title: Leishmania histone H1 overexpression delays parasite cell-cycle progression, parasite differentiation and reduces Leishmania infectivity in vivo.
abstract: Episomal expression of Leishmania histone H1 sense mRNAs in Leishmania major promastigotes was found previously to result in overexpression of this molecule and to reduce parasite infectivity in vitro. Herein, we evaluated the in vivo infectivity of these transfectants, in BALB/c mice, and showed that it is dramatically reduced. No lesions were observed in this group of mice and this was associated with an extremely low number of parasites both in the footpad and in the draining lymph nodes. Interestingly, the transfectants-reduced infectivity was associated with a delay in their cell-cycle progression and differentiation to axenic amastigotes, assessed in vitro. Therefore, the dramatic reduction in their infectivity may be attributed to the above-mentioned phenotypic modifications. As the metazoan linker histone H1(0) homologue is known to delay cell-cycle progression in mammalian cells we investigated whether its Leishmania counterpart, which possesses homology to its C-terminal region, when expressed in mammalian cells may also affect their cell-cycle progression. It was thus shown that Leishmania histone H1 expressed in COS7 and NIH 3T3 cells, delays cell-cycle progression in these cells too. The latter strengthens the phenotype observed in Leishmania and provides evidence that critical functions of histone H1 molecules are conserved throughout evolution.
authors.affiliation: Department of Microbiology, Laboratory of Molecular Parasitology, Hellenic Pasteur Institute, 127 Bas. Sofias Avenue, 115 21 Athens, Greece.
authors.forename: Despina
authors.initials: D
authors.lastname: Smirlis
authors.forename: Sylvia N
authors.initials: SN
authors.lastname: Bisti
authors.forename: Evangelia
authors.initials: E
authors.lastname: Xingi
authors.forename: Georgia
authors.initials: G
authors.lastname: Konidou
authors.forename: Maria
authors.initials: M
authors.lastname: Thiakaki
authors.forename: Ketty P
authors.initials: KP
authors.lastname: Soteriadou
mesh_terms: D000818:Animals; D019556:COS Cells; D002453:Cell Cycle / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics; D002522:Chlorocebus aethiops; D006657:Histones / Q000235:genetics*; D007893:Leishmania donovani / Q000166:cytology / Q000235:genetics; D018320:Leishmania major / Q000166:cytology / Q000235:genetics* / Q000472:pathogenicity*; D051379:Mice; D008807:Mice, Inbred BALB C; D041681:NIH 3T3 Cells; D015739:Nocodazole / Q000494:pharmacology; D015800:Protozoan Proteins / Q000235:genetics*; D015533:Transcriptional Activation; D014774:Virulence / Q000235:genetics
chemical_list: D006657:Histones; D015800:Protozoan Proteins; D015739:Nocodazole