Abstract
AbstractGerm line specification is essential in sexually reproducing organisms. Despite their critical role, the evolutionary history of the genes that specify animal germ cells is heterogeneous and dynamic. In many insects, the geneoskaris required for the specification of the germ line. However, the germ line role ofoskaris thought to be a derived role resulting from co-option from an ancestral somatic role. To address how evolutionary changes in protein sequence could have led to changes in the function of Oskar protein that enabled it to regulate germ line specification, we searched foroskarorthologs in 1565 publicly available insect genomic and transcriptomic datasets. The earliest-diverging lineage in which we identified anoskarortholog was the order Zygentoma (silverfish and firebrats), suggesting thatoskaroriginated before the origin of winged insects. We noted some order-specific trends inoskarsequence evolution, including whole gene duplications, clade-specific losses, and rapid divergence. An alignment of all known 379 Oskar sequences revealed new highly conserved residues as candidates that promote dimerization of the LOTUS domain. Moreover, we identified regions of the OSK domain with conserved predicted RNA binding potential. Furthermore, we show that despite a low overall amino acid conservation, the LOTUS domain shows higher conservation of predicted secondary structure than the OSK domain. Finally, we suggest new key amino acids in the LOTUS domain that may be involved in the previously reported Oskar-Vasa physical interaction that is required for its germ line role.
Publisher
Cold Spring Harbor Laboratory
Reference137 articles.
1. Patterns of molecular evolution of the germ line specification gene oskar suggest that a novel domain may contribute to functional divergence in Drosophila;Development Genes and Evolution,2014
2. The embryology of Habobracon juglandis (Ashmead);Journal of Morphology,1961
3. Anantharaman V , Zhang D , Aravind L . (p15752 co-authors). 2010. OST-HTH: a novel predicted RNA-binding domain. Biology direct 5:13.
4. The morphological basis of embryonic movements in the light brown apple moth, Epiphyas postvittana (Walk.) (Lepidoptera, Tortricidae);Australian Journal of Zoology,1968
5. Early embryonic devekopment of the primitive moths, Enduclyta signifer Walker and E. excrescens Butler (Lepidoptera: Hepialidae);International Journal of Insect Morphology and Embryology,1979