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Insulin‐like genes in ascidians: Findings in C iona and hypotheses on the evolutionary origins of the pancreas
Author(s) -
Thompson Jordan M.,
Di Gregorio Anna
Publication year - 2015
Publication title -
genesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.093
H-Index - 110
eISSN - 1526-968X
pISSN - 1526-954X
DOI - 10.1002/dvg.22832
Subject(s) - chordate , ciona , ciona intestinalis , biology , notochord , brachyury , deuterostome , insulin , vertebrate , microbiology and biotechnology , gene , mesoderm , genetics , endocrinology , embryogenesis , embryonic stem cell
Insulin plays an extensively characterized role in the control of sugar metabolism, growth and homeostasis in a wide range of organisms. In vertebrate chordates, insulin is mainly produced by the beta cells of the endocrine pancreas, while in non‐chordate animals insulin‐producing cells are mainly found in the nervous system and/or scattered along the digestive tract. However, recent studies have indicated the notochord, the defining feature of the chordate phylum, as an additional site of expression of insulin‐like peptides. Here we show that two of the three insulin‐like genes identified in Ciona intestinalis , an invertebrate chordate with a dual life cycle, are first expressed in the developing notochord during embryogenesis and transition to distinct areas of the adult digestive tract after metamorphosis. In addition, we present data suggesting that the transcription factor Ciona Brachyury is involved in the control of notochord expression of at least one of these genes, Ciona insulin‐like 2 . Finally, we review the information currently available on insulin‐producing cells in ascidians and on pancreas‐related transcription factors that might control their expression. genesis 53:82–104, 2015. © 2014 Wiley Periodicals, Inc.