Gene expression profile in selenophosphate synthetase 1 (SPS1) knockdown Drosophila SL2 cell

Selenophosphate, which is the active donor of selenium in selenocysteine (Sec) biosynthesis is synthesized from selenite and ATP by an enzyme designated as selenophosphate synthetase (SPS).There are two isoforms of SPS in higher eukaryotes,SPS1 and SPS2. Initially, both SPS1 and SPS2 were thought to be involved in selenophosphate synthesis. However, it was subsequently shown that only SPS2 catalyzes selenophosphate synthesis. Although SPS1 is an essential gene in Drosophila, its function has not been determined. To identify transcriptional profile of SPS1 knockdown cells, which could offer valuable clues to identify molecular mechanism of SPS1, we introduced RNAi using its cognate double-stranded RNA into Drosophila SL2 cells, and then microarray analysis was carried out. In order to find primary or secondary target gene which is regulated by SPS1,Drosophila SL2 cells were harvested at day1, day3 and day5 after SPS1 knockown for RNA extraction and hybridization on Affymetrix microarrays.

硒磷酸（selenophosphate）是硒代半胱氨酸（selenocysteine, Sec）生物合成过程中的活性硒供体，可由亚硒酸盐与ATP通过一种命名为硒磷酸合成酶（selenophosphate synthetase, SPS）的酶催化合成。高等真核生物中存在两种SPS同工型，即SPS1与SPS2。最初学界认为SPS1和SPS2均参与硒磷酸的合成，但后续研究证实仅SPS2可催化硒磷酸的生成。尽管SPS1是果蝇（Drosophila）的必需基因，但其具体生物学功能至今尚未明确。为鉴定SPS1敲低细胞的转录表达谱，从而为阐明SPS1的分子调控机制提供有价值的线索，我们将针对SPS1的同源双链RNA介导的RNA干扰（RNA interference, RNAi）导入果蝇SL2细胞，随后开展基因芯片分析。为筛选受SPS1调控的一级与二级靶基因，我们在SPS1敲低后的第1天、第3天及第5天收集果蝇SL2细胞，提取总RNA并在Affymetrix基因芯片上完成杂交实验。