title: Plasmodium falciparum: effect of radiation on levels of gene transcripts in sporozoites.
abstract: Humans immunized by the bites of irradiated Plasmodium falciparum (Pf) sporozoite-infected mosquitoes are protected against malaria. Radiation attenuates the sporozoites preventing them from fully developing and replicating in hepatocytes, but the effects of radiation on gene expression in sporozoites are unknown. We used RT-PCR (35 cycles of PCR followed by densitometry) to assess the expression of ten genes in Pf sporozoites, and in sporozoites irradiated with 15,000cGy. Irradiation reduced expression substantially (>60%) of two DNA repair genes; moderately (30-60%) of PfUIS3, the Pf orthologue of PbUIS3, a gene up-regulated in Plasmodium berghei sporozoites and of a third DNA repair gene; and minimally (<30%) of the Pf18S ribosomal RNA, PfCSP, PfSSP2/TRAP, and PfCELTOS genes. Irradiation increased expression of PfSPATR minimally. PfLSA1 RNA was not detectable in sporozoites. These results establish that radiation of sporozoites affects gene expression levels and provide the foundation for studies to identify specific genes involved in attenuation and protective immunity.
authors.affiliation: Protein Potential LLC, 9800 Medical Center Drive, Rockville, MD 20850, USA. benjaminhoffman@mac.com
authors.forename: Benjamin U
authors.initials: BU
authors.lastname: Hoffman
authors.forename: Rana
authors.initials: R
authors.lastname: Chattopadhyay
mesh_terms: D000818:Animals; D004260:DNA Repair / Q000235:genetics; D018076:DNA, Complementary / Q000032:analysis / Q000096:biosynthesis; D015870:Gene Expression / Q000528:radiation effects*; D017780:Malaria Vaccines; D008565:Membrane Proteins / Q000235:genetics; D010963:Plasmodium falciparum / Q000235:genetics / Q000528:radiation effects*; D015800:Protozoan Proteins / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D034101:Sporozoites / Q000528:radiation effects; D014613:Vaccines, Attenuated
chemical_list: D018076:DNA, Complementary; D017780:Malaria Vaccines; D008565:Membrane Proteins; D015800:Protozoan Proteins; D012337:RNA, Ribosomal, 18S; D014613:Vaccines, Attenuated