Multiple functions of shutdown in Drosophila germline development

Abstract

In animals, maintenance of the germline genomic integrity is crucial for accurate transmission of genetic information to the next generation. A unique small RNA pathway known as the PIWI-interacting RNA (piRNA) pathway is present in the animal germline to prevent transposable elements from subverting genomic integrity. Loss of function of several piRNA pathway components often leads to sterility. The Drosophila gene, shutdown, was recently reported to be a component of the piRNA pathway in the ovaries. Shutdown is evolutionarily conserved and shows homology to the FK506-binding protein 6, which has an essential role for male fertility in mouse and human. In this study, analysis of the phenotype of Drosophila shutdown mutant testis demonstrates that shutdown is essential for the localization of the PIWI proteins and is involved in the piRNA pathway in the testis. shutdown is also required to maintain fertility in Drosophila males. In addition, knockdown of shutdown in the germline and somatic compartments of the ovaries reveal a piRNA pathway-independent function of shutdown in the germline for egg production.