The DExH box helicase domain of spindle-E is necessary for retrotransposon silencing and axial patterning during Drosophila oogenesis.
Bottom Line: Of the alleles that express detectable Spindle-E protein, we found that five had mutations in the DExH box domain.The phenotype of many of these alleles is as severe as the strongest spindle-E phenotype, whereas alleles with mutations in other regions of Spindle-E did not affect these processes as much.From these data we conclude that the DExH box domain of Spindle-E is necessary for its function in the piRNA pathway and retrotransposon silencing.
Affiliation: Department of Medicine, Biomedical Genetics, Boston University School of Medicine, Boston, Massachusetts 02118 Graduate Program in Genetics and Genomics, Boston University School of Medicine, Boston, Massachusetts 02118.Show MeSH
Related in: MedlinePlus
Mentions: A critical protein involved in the generation of most germ cell piRNA species is Drosophila Spindle-E (Malone et al. 2009). SPN-E colocalizes to the nuage along with other piRNA pathway proteins and its function is required for either primary piRNA generation and/or the ping-pong cycle (Malone et al. 2009; Patil and Kai 2010). spn-E was originally identified as a gene necessary for microtubule network formation, RNA localization, and embryonic pattern formation (Gillespie and Berg 1995; Klattenhoff et al. 2007; Martin et al. 2003). However, it is not known whether SPN-E function in the piRNA pathway controls all of these processes. The SPN-E protein contains a DExH box helicase domain, a Tudor domain, and a Zinc finger (Zn), which implicate its function in RNA processing, translational regulation, RNA decay, splicing, or protein–protein interactions (Figure 1, A and B). However, the relative contribution of these domains to SPN-E function, particularly in the piRNA pathway, is currently unknown. Therefore, to begin to understand how SPN-E functions during oogenesis, particularly in TE silencing, we took advantage of several previously isolated spn-E mutant fly lines in an attempt to identify mutations in the predicted functional domains. Our results provide evidence that the DExH box helicase domain of SPN-E is necessary for TE silencing in the germline.
Affiliation: Department of Medicine, Biomedical Genetics, Boston University School of Medicine, Boston, Massachusetts 02118 Graduate Program in Genetics and Genomics, Boston University School of Medicine, Boston, Massachusetts 02118.