title: Multiple Roles for Egalitarian in Polarization of the Drosophila Egg Chamber.
abstract: The Drosophila egg chamber provides a useful model for examining mechanisms by which cell fates are specified and maintained in the context of a complex tissue. The egg chamber is also an excellent model for understanding the mechanism by which cytoskeletal filaments are organized and the critical interplay between cytoskeletal organization, polarity establishment, and cell fate specification. Previous work has shown that Egalitarian (Egl) is required for specification and maintenance of oocyte fate. Mutants in egl either completely fail to specify an oocyte, or if specified, the oocyte eventually reverts back to nurse cell fate. Due to this very early role for Egl in egg chamber maturation, it is unclear whether later stages of egg chamber development also require Egl function. In this report, we have depleted Egl at specific stages of egg chamber development. We demonstrate that in early-stage egg chambers, Egl has an additional role in organization of oocyte microtubules. In the absence of Egl function, oocyte microtubules completely fail to reorganize. As such, the localization of microtubule motors and their cargo is disrupted. In addition, Egl also appears to function in regulating the translation of critical polarity determining messenger RNAs (mRNAs). Finally, we demonstrate that in midstage egg chambers, Egl does not appear to be required for microtubule organization, but rather for the correct spatial localization of oskar, bicoid, and gurken mRNAs.
authors.affiliation: Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia 30912.
authors.forename: Paulomi
authors.initials: P
authors.lastname: Sanghavi
authors.affiliation: Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia 30912.
authors.forename: Guojun
authors.initials: G
authors.lastname: Liu
authors.affiliation: Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia 30912.
authors.forename: Rajalakshmi
authors.initials: R
authors.lastname: Veeranan-Karmegam
authors.affiliation: Biomedical Genetics, Boston University School of Medicine, Massachusetts 02118.
authors.forename: Caryn
authors.initials: C
authors.lastname: Navarro
authors.affiliation: Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia 30912 ggonsalvez@augusta.edu.
authors.forename: Graydon B
authors.initials: GB
authors.lastname: Gonsalvez
mesh_terms: D000818:Animals; D004330:Drosophila / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D008870:Microtubules / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D009866:Oogenesis / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D012333:RNA, Messenger; C104613:egl protein, Drosophila
keywords: RNA localization; cell polarity; microtubule organization; molecular motor