title: Plasmodium falciparum DOZI, an RNA helicase interacts with eIF4E.
abstract: DEAD box RNA helicases play crucial roles in RNA metabolism such as splicing, ribosome biogenesis, RNA transport, degradation and translation. DDX6/DOZI (development of zygote inhibited) is one of the well characterized member of the DEAD box family and is highly conserved from humans to malaria parasite. DDX6 is involved in a variety of biological processes, which include the sexual development of the protozoan parasite. In the present manuscript we report that P. falciparum DOZI (DDX6 homologue); PfDZ50 contains the characteristic DNA and RNA binding, nucleic acid-dependent ATPase and RNA unwinding activities. Enzymatic characterization of truncated derivatives of PfDZ50 such as PfDZ50T1 (domain 1) and PfDZ50T2 (domain 2) shows that none of them contains ATPase activity. Furthermore, we confirmed that PfDZ50 interacts with PfeIF4E mainly through domain 1. Using in vitro translation assays we show that PfDZ50 inhibits translation. With the same assays we further report that externally added PfeIF4E restores ~70% of translation. Using immunofluorescence assays we demonstrate that PfDZ50 is localized mainly in the cytoplasm in the asexual intraerythrocytic developmental stages of P. falciparum. The localization pattern further suggests that PfDZ50 appears typically in granular bodies throughout the cytoplasm. Thus these studies will advance our knowledge regarding the function of PfDZ50/DDX6 in general.
authors.affiliation: Malaria Group, International Centre for Genetic Engineering and Biotechnology, P. O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Tarique
authors.forename: Moaz
authors.initials: M
authors.lastname: Ahmad
authors.forename: Abulaish
authors.initials: A
authors.lastname: Ansari
authors.forename: Renu
authors.initials: R
authors.lastname: Tuteja
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism*; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020539:Sequence Analysis, Protein
chemical_list: D004268:DNA-Binding Proteins; D039561:Eukaryotic Initiation Factor-4E; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D016601:RNA-Binding Proteins; D000251:Adenosine Triphosphatases; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases