title: Asymmetric localization of Drosophila pair-rule transcripts from displaced nuclei: evidence for directional nuclear export.
abstract: Drosophila pair-rule transcripts accumulate exclusively apical of the layer of peripheral nuclei in syncytial blastoderm stage embryos. Here, we use aneuploid embryos to test zygotic gene requirements for pair-rule transcript localization. As apical localization is maintained in all genotypes tested, the required components must be maternally encoded. In aneuploid embryos with multiple layers or cortical nuclei, pair-rule transcripts lie apical of both superficial and internalized nuclei. In the latter case, the transcripts are 'pseudo-apical', i.e. apical of the nuclei from which they derive, but basal of superficial nuclei. We show that internalized nuclei maintain their apico-basal nuclear orientation, and that they lack the apical cytoskeletal assemblies which lie adjacent to superficial nuclei. These results support a mechanism of localizing pair-rule transcripts by directional (vectorial) nuclear export.
authors.affiliation: Zoology Department, University of Oxford, UK.
authors.forename: H
authors.initials: H
authors.lastname: Francis-Lang
authors.forename: I
authors.initials: I
authors.lastname: Davis
authors.forename: D
authors.initials: D
authors.lastname: Ish-Horowicz
mesh_terms: D000782:Aneuploidy; D000818:Animals; D001693:Biological Transport, Active; D002467:Cell Nucleus / Q000378:metabolism; D016764:Cell Polarity / Q000235:genetics; D003593:Cytoplasm / Q000378:metabolism; D004330:Drosophila / Q000196:embryology / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D008297:Male; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger