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Structure, expression, and biological function of INSM1 transcription factor in neuroendocrine differentiation
Author(s) -
Lan Michael S.,
Breslin Mary B.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.08-125971
Subject(s) - neurod , biology , zinc finger transcription factor , transcription factor , enteroendocrine cell , neurogenesis , microbiology and biotechnology , neuroendocrine differentiation , cellular differentiation , pax6 , embryonic stem cell , zinc finger , endocrinology , medicine , endocrine system , gene , genetics , hormone , prostate cancer , cancer
Zinc‐finger transcription factors are DNAbinding proteins that are implicated in many diverse biological functions. INSM1 (formerly IA‐1) contains five zinc‐finger motifs and functions as a transcription factor. INSM1 protein structure is highly conserved in homologues of different species. It is predominantly expressed in developing neuroendocrine tissues and the nervous system in mammals. INSM1 represents an important player in early embryonic neurogenesis. In pancreatic endocrine cell differentiation, Ngn3 first activates INSM1 and subsequently NeuroD/P2. Conversely, INSM1 exerts a feedback mechanism to suppress NeuroD/P2 and its own gene expression. INSM1 gene ablation in the mouse results in the impairment of pancreatic endocrine cell maturation. Further, deletion of INSM1 severely impairs catecholamine biosynthesis and secretion from the adrenal gland that results in early embryonic lethality. Genetically, INSM1 acts as a downstream factor of Mash 1 and Phox2b in the differentiation of the sympatho‐adrenal lineage. In the developing neocortex, mouse embryos lacking INSM1 expression contain half the number of basal progenitors and show a reduction in cortical plate radial thickness. Cell signaling studies reveal that INSM1 contributes to the induction of cell cycle arrest/exit necessary to facilitate cellular differentiation. INSM1 is highly expressed in tumors of neuroendocrine origin. Hence, its promoter could serve as a tumor‐specific promoter that drives a specific targeted cancer gene therapy for the treatment of neuroendocrine tumors. Taken together, all of these features of INSM1 strongly support its role as an important regulator during neuroendocrine differentiation.—Lan, M. S., Breslin, M. B. Structure, expression, and biological function of INSM1 transcription factor in neuroendocrine differentiation. FASEB J. 23, 2024–2033 (2009)