The Toxoplasma gondii Plastid replication and Repair Enzyme complex, PREX

Mukhopadhyay, A., Chen, C.Y., Doerig, C., Henriquez, F.L., Roberts, C.W. and Barrett, M.P. (2009) The Toxoplasma gondii Plastid replication and Repair Enzyme complex, PREX. Parasitology, 136(7), pp. 747-755. (doi: 10.1017/S0031182009006027)

Abstract

A plastid-like organelle, the apicoplast, is essential to the majority of medically and veterinary important apicomplexan protozoa including Toxoplasma gondii and Plasmodium. The apicoplast contains multiple copies of a 35 kb genome, the replication of which is dependent upon nuclear-encoded proteins that are imported into the organelle. In P. falciparum an unusual multi-functional gene, pfprex, was previously identified and inferred to encode a protein with DNA primase, DNA helicase and DNA polymerase activities. Herein, we report the presence of a prex orthologue in T. gondii. The protein is predicted to have a bi-partite apicoplast targeting sequence similar to that demonstrated on the PfPREX polypeptide, capable of delivering marker proteins to the apicoplast. Unlike the P. falciparum gene that is devoid of introns, the T. gondii prex gene carries 19 introns, which are spliced to produce a contiguous mRNA. Bacterial expression of the polymerase domain reveals the protein to be active. Consistent with the reported absence of a plastid in Cryptosporidium species, in silico analysis of their genomes failed to demonstrate an orthologue of prex. These studies indicate that prex is conserved across the plastid-bearing apicomplexans and may play an important role in the replication of the plastid genome.

• Item Type: Articles
• Keywords: Apicomplexa; DNA replication; Plasmodium falciparum; Toxoplasma gondii, exon, intron, DNA polymerase, DNA primase, DNA helicase
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Doerig, Dr Christian and Barrett, Professor Michael and Mukhopadhyay, Dr Arunima
• Authors: Mukhopadhyay, A., Chen, C.Y., Doerig, C., Henriquez, F.L., Roberts, C.W., and Barrett, M.P.
• Subjects: Q Science > QR Microbiology > QR180 Immunology; Q Science > QR Microbiology
• College/School: College of Medical Veterinary and Life Sciences; College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: Parasitology
• ISSN: 0031-1820
• ISSN (Online): 1469-8161