Drosophila dec-1 Eggshell Proteins Are Differentially Distributed via a Multistep Extracellular Processing and Localization Pathway

• Published in: Developmental biology 2000-09, Vol.225 (2), p.459-470
• Main Authors: Noguerón, M.Isabel, Mauzy-Melitz, Debra, Waring, Gail L
• Format: Article
• Language: English
• Subjects: Alternative Splicing; Animals; Animals, Genetically Modified; Chorion - cytology; Chorion - physiology; dec-1 gene; dec-1 protein; Drosophila; Drosophila melanogaster - embryology; Drosophila melanogaster - physiology; Drosophila Proteins; Egg Proteins - genetics; Egg Proteins - physiology; Egg Shell; eggshell; Embryo, Nonmammalian - physiology; Embryonic Induction; extracellular assembly; Female; immunolocalization; Insect Proteins - genetics; Insect Proteins - physiology; Oocytes - physiology; Oogenesis - physiology; Protein Precursors - genetics; protein trafficking; Recombinant Fusion Proteins - metabolism; Transcription, Genetic
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1006/dbio.2000.9805

In Drosophila the multilayered eggshell forms during late oogenesis between the oocyte and the overlaying follicle cells. Proper eggshell assembly requires wild-type dec-1 gene function. Alternatively spliced dec-1 transcripts encode three proproteins that are cleaved extracellularly in a stage-specific manner to at least five distinct derivatives. Using polyclonal antibodies raised against fusion proteins containing different regions of the dec-1 proteins, we have localized several dec-1 derivatives in the assembling and completed eggshell. Although all of the dec-1 derivatives are generated in the oocyte proximal vitelline membrane layer, they are differentially distributed in the mature egg. Some derivatives are gradually released from the vitelline membrane and become localized within distinct regions of the chorion, while others are taken up by the oocyte or become concentrated in the endochorionic spaces or cavities. The diverse distributions of the dec-1 derivatives suggest that each derivative plays a distinct role in eggshell assembly. These results also suggest that the vitelline membrane layer, by acting as a transient storage site, may control the availability of molecules active in eggshell assembly and by extension perhaps other follicle cell products important in early embryonic pattern formation.