Hoffman Benjamin U, Chattopadhyay Rana
Protein Potential LLC, 9800 Medical Center Drive, Rockville, MD 20850, USA.
Exp Parasitol. 2008 Feb;118(2):247-52. doi: 10.1016/j.exppara.2007.08.014. Epub 2007 Sep 6.
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.
被经辐射的恶性疟原虫（Pf）子孢子感染的蚊子叮咬免疫的人类可预防疟疾。辐射使子孢子衰减，阻止它们在肝细胞中充分发育和复制，但辐射对子孢子基因表达的影响尚不清楚。我们使用逆转录聚合酶链反应（RT-PCR，35个循环的PCR，随后进行光密度测定）来评估Pf子孢子以及经15000厘戈瑞辐射的子孢子中十个基因的表达。辐射使两个DNA修复基因的表达大幅降低（>60%）；使PfUIS3（PbUIS3的Pf直系同源基因，该基因在伯氏疟原虫子孢子中上调）和第三个DNA修复基因的表达中度降低（30 - 60%）；使Pf18S核糖体RNA、PfCSP、PfSSP2/TRAP和PfCELTOS基因的表达轻微降低（<30%）。辐射使PfSPATR的表达轻微增加。在子孢子中未检测到PfLSA1 RNA。这些结果表明子孢子的辐射会影响基因表达水平，并为鉴定参与衰减和保护性免疫的特定基因的研究奠定了基础。
