title: The DExH box helicase domain of spindle-E is necessary for retrotransposon silencing and axial patterning during Drosophila oogenesis.
abstract: Transposable selfish genetic elements have the potential to cause debilitating mutations as they replicate and reinsert within the genome. Therefore, it is critical to keep the cellular levels of these elements low. This is especially true in the germline where these mutations could affect the viability of the next generation. A class of small noncoding RNAs, the Piwi-associated RNAs, is responsible for silencing transposable elements in the germline of most organisms. Several proteins have been identified as playing essential roles in piRNA generation and transposon silencing. However, for the most part their function in piRNA generation is currently unknown. One of these proteins is the Drosophila melanogaster DExH box/Tudor domain protein Spindle-E, whose activity is necessary for the generation of most germline piRNAs. In this study we molecularly and phenotypically characterized 14 previously identified spindle-E alleles. Of the alleles that express detectable Spindle-E protein, we found that five had mutations in the DExH box domain. Additionally, we found that processes that depend on piRNA function, including Aubergine localization, Dynein motor movement, and retrotransposon silencing, were severely disrupted in alleles with DExH box domain mutations. 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.
authors.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.
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Ott
authors.affiliation: Department of Medicine, Biomedical Genetics, Boston University School of Medicine, Boston, Massachusetts 02118.
authors.forename: Tram
authors.initials: T
authors.lastname: Nguyen
authors.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 cnavarro@bu.edu.
authors.forename: Caryn
authors.initials: C
authors.lastname: Navarro
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics* / Q000502:physiology; D004398:Dyneins / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D020868:Gene Silencing; D008969:Molecular Sequence Data; D009866:Oogenesis / Q000235:genetics*; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000235:genetics; D018626:Retroelements
chemical_list: D029721:Drosophila Proteins; D010448:Peptide Initiation Factors; D034741:RNA, Small Interfering; D018626:Retroelements; C436124:aub protein, Drosophila; D000251:Adenosine Triphosphatases; C096355:spn-E protein, Drosophila; D004398:Dyneins
keywords: Drosophila; RNA helicase; embryonic patterning; oogenesis; piRNA; retrotransposon