title: Molecular characterization and expression of an alternate proliferating cell nuclear antigen homologue, PfPCNA2, in Plasmodium falciparum.
abstract: The malaria parasite Plasmodium falciparum genome sequencing has revealed the existence of a second gene for proliferating cell nuclear antigen (PCNA), a key factor in a variety of DNA metabolic events. The alternate copy of PCNA (PfPCNA2) shows only 23% identity to an earlier reported P. falciparum PCNA homologue (PfPCNA1). Our analysis indicated structural conservation of PfPCNA2 compared to eukaryotic PCNAs. PfPCNA1 and 2 polypeptides showed differential expression in the intraerythrocytic cell cycle of the malaria parasite. PfPCNA1 expression slowly increases about threefold from the ring to the late schizont stage. In contrast PfPCNA2 showed robust expression in trophozoites and early schizonts with a sudden drop in expression in the late schizont stage, suggesting that the two PfPCNAs may function under different physiological conditions. Chemical cross-linking indicated the presence of a trimeric PfPCNA2 protein, indicating the possible existence of a functional ring-like PfPCNA2 structure.
authors.affiliation: Department of Molecular Biology and Microbiology, University of Central Florida, Orlando, FL 32826, USA.
authors.forename: Shelley
authors.initials: S
authors.lastname: Patterson
authors.forename: Christina
authors.initials: C
authors.lastname: Whittle
authors.forename: Claudia
authors.initials: C
authors.lastname: Robert
authors.forename: Debopam
authors.initials: D
authors.lastname: Chakrabarti
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001704:Biopolymers; D017931:DNA Primers; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000276:immunology*; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
chemical_list: D001704:Biopolymers; D017931:DNA Primers; D018809:Proliferating Cell Nuclear Antigen