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SUMMARY:Dorsal closure in dipterans: epithelial rupture\, contraction and 
 seaming in embryos of the scuttle fly Megaselia abdita - Juan Fraire-Zamor
 a (Centre for Genomic Regulation\, Barcelona)
DTSTART:20180425T120000Z
DTEND:20180425T130000Z
UID:TALK104359@talks.cam.ac.uk
CONTACT:Olivia Tidswell
DESCRIPTION:The evolution of morphogenesis is generally assumed to be asso
 ciated with changes in genetic patterns that lead to the spatial reorganiz
 ation of tissues. I will present a case study where rearrangements of epit
 helial organization occur without major changes in genetic patterning. In 
 Drosophila melanogaster\, the process of dorsal closure consists of the fu
 sion of opposing epithelial sheets where a contractile extraembryonic amni
 oserosa and a JNK/Dpp-dependent epidermal actomyosin cable result in a mic
 rotubule-dependent seaming of the epidermis. In the scuttle fly Megaselia 
 abdita\, dorsal closure must occur in the presence of a separate serosa\, 
 amnion and epidermis. It differs from Drosophila in morphogenetic rearrang
 ements despite conservation of the JNK/Dpp signaling pathway. Using a quan
 titative approach in a non-model organism\, we show that dorsal closure in
  M. abdita is driven by the rupture and contraction of the serosa\, an epi
 dermal actomyosin cable and the consecutive microtubule-dependent seaming 
 of amnion and epidermis. Using high-resolution time-lapse imaging\, immuno
 staining and molecular tools\, we obtained evidence indicating that the ev
 olutionary transition to a reduced system of dorsal closure involves the s
 implification of the seaming process without changing the signaling pathwa
 ys of closure progression.
LOCATION:Part II Lecture Theatre\, Department of Zoology
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