Show simple item record

Localisation and function of Slam in the early Drosophila embryo

dc.contributor.advisorGroßhans, Jörg Prof. Dr.
dc.contributor.authorAcharya, Sreemukta
dc.titleLocalisation and function of Slam in the early Drosophila embryode
dc.contributor.refereeSchuh, Reinhard Prof. Dr.
dc.description.abstractengEmbryogenesis of many insects starts with a syncytial stage characterised by 13 rapid nuclear divisions. During the following interphase, the plasma membrane of the embryo invaginates between each nucleus to give rise to the first epithelial layer of the embryo. This type of cytokinesis during interphase has been named cellularisation. Two important processes involved in cellularisation are a) specification of the site of cleavage furrow and b) initiation and maintenance of membrane invagination. We investigated the role of a gene slam in these processes. Although it has been shown earlier that slam is necessary for cellularisation and the formation of the basal domain of the invaginating membrane (furrow canal), it has remained unclear how Slam reaches the furrow canal and interacts with the membrane. The aim of the study was to uncover the mechanism of Slam accumulation at the furrow canal, elucidate its mobility dynamics at the membrane and elaborate its role in cellularisation. By means of live imaging and centrosome ablation, I could show that centrosomes are the initial source of signals for the accumulation of Slam. Using shibire temperature-sensitive mutants, I found that the initial accumulation of Slam at the new furrow was vesicle-dependent but its maintenance at the old furrow was not. Analysis of nuf mutants revealed that although Slam is not directly transported on Rab11-positive vesicles, its proper targeting to the basal domain is indirectly dependent upon the recycling endosome. I identified a role of slam together with another gene nullo in establishing the furrow. I found that slam and nullo act redundantly to each other. Furthermore, using fluorescent recovery after photobleaching experiments, I could show that membrane-associated Slam undergoes a switch-like change from high mobility at the onset of cellularisation to low mobility at mid-cellularisation. Slam mobility in mid-cellularisation is independent of new translation and vesicular trafficking. Finally, I showed that Slam is a ribonucleoprotein complex (RNP) and that slam mRNA was more enriched at the membrane. I propose that the recycling endosome that is organised by the centrosome restricts a potential Slam receptor to the prospective basal domain of the membrane to which the Slam RNP is recruited from the cytoplasm. Once at the furrow, slam acts together with nullo to establish the furrow and initiate cellularisation without further recruitment of Slam RNP and Slam protein
dc.contributor.coRefereeUrlaub, Henning Prof. Dr.
dc.affiliation.instituteGöttinger Graduiertenschule für Neurowissenschaften, Biophysik und molekulare Biowissenschaften (GGNB)de
dc.subject.gokfullBiologie (PPN619462639)de

Files in this item


This item appears in the following Collection(s)

Show simple item record