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Xenopus Insm1 is essential for gastrointestinal and pancreatic endocrine cell development
Author(s) -
Horb Lori Dawn,
Jarkji Zeina H.,
Horb Marko E.
Publication year - 2009
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.22071
Subject(s) - neurod , biology , enteroendocrine cell , endocrine system , pancreas , transcription factor , pax6 , gene knockdown , medicine , microbiology and biotechnology , endocrinology , gene , genetics , hormone
In mammals, it has been well established that gastrointestinal and pancreatic endocrine cells are specified by a cascade of different transcription factors, but whether these same pathways (or linear relationships) operate in Xenopus is currently unknown. We recently identified the endocrine‐specific zinc finger transcription factor insulinoma associated protein 1 ( insm1 ) as a dorsal‐enriched gene. We found that insm1 is expressed in the dorsal pancreas as early as NF28, making it one of the earliest markers to be localized to the dorsal pancreas. Through morpholino‐mediated knockdown, we demonstrate that insm1 is essential for proper specification of both gastrointestinal and pancreatic endocrine cells. In addition, we place insm1 downstream of ngn3 and upstream of pax6 and neuroD in the endocrine cell transcription factor cascade. These are the first results showing that the endodermal endocrine cell development in Xenopus uses the same transcriptional cascade as in mammals. Developmental Dynamics 238:2505–2510, 2009. © 2009 Wiley‐Liss, Inc.