PgmNr Z6055: Role of Snail1b in migration of Posterior Lateral Line primodium.

Authors:
U. M. Neelathi 1 ; A. B. Chitnis 2


Institutes
1) NIH, Bethesda, MD; 2) NIH, Bethesda, MD.


Abstract:

Authors   Uma M Neelathi and Ajay B Chitnis

Collective cell migration, is an important event in embryonic development, wound healing and cancer metastasis. Posterior Lateral line primodium (PLLp) presents an excellent model for studying collective cell migration. Its a group of 100 cells, from ectodermal placodes behind the otic vesicle migrates along the horizoantl myoseptum depostiing neuromasts at regular intervals, which constitutes the lateral line sensory system. While the leading PLLp cohort maintain mesenchymal cellualrity thorugh Wnt signaling. The trailing epithelial cell types are conferred via a Wnt dependant Fgf signaling, which are organised into rossettes that are deposited as neuromasts. Factos, which make the pseudo epithelial to mesemchymal transition of the primodium cells during migration, are not known. Expression analysis of various mesenchymal genes by RNA in situ, identified Snail1b in the leading doamin at 22hpf when primodium initiates its migration. Snail1b is positively regualted by Sdf1a in the leading domain and negatively by Fgf singaling in the trailing domain. Morpholino based loss of function of Snail1b cause a delay in initiation and reduced speed of migration of PLLp compared to the controls. The delay in initiation and rate of migration is though imbalance between the Wnt and Fgf signaling systems in the PLLp. Absence or a total loss of migration of PLLp could possibley due to partial knockdwon of Snail1b or by other compensatory complementary genes. Our data suggest that Snail1b is necessary in breaking the symmetry of Wnt signaling and giving in way for Fgf signaling to estbalsih and initiation of the primodium migration.



ZFIN Genetics Index
1. Snail1b