title: Tcf19 is a novel islet factor necessary for proliferation and survival in the INS-1 β-cell line.
abstract: Recently, a novel type 1 diabetes association locus was identified at human chromosome 6p31.3, and transcription factor 19 (TCF19) is a likely causal gene. Little is known about Tcf19, and we now show that it plays a role in both proliferation and apoptosis in insulinoma cells. Tcf19 is expressed in mouse and human islets, with increasing mRNA expression in nondiabetic obesity. The expression of Tcf19 is correlated with β-cell mass expansion, suggesting that it may be a transcriptional regulator of β-cell mass. Increasing proliferation and decreasing apoptotic cell death are two strategies to increase pancreatic β-cell mass and prevent or delay diabetes. siRNA-mediated knockdown of Tcf19 in the INS-1 insulinoma cell line, a β-cell model, results in a decrease in proliferation and an increase in apoptosis. There was a significant reduction in the expression of numerous cell cycle genes from the late G1 phase through the M phase, and cells were arrested at the G1/S checkpoint. We also observed increased apoptosis and susceptibility to endoplasmic reticulum (ER) stress after Tcf19 knockdown. There was a reduction in expression of genes important for the maintenance of ER homeostasis (Bip, p58(IPK), Edem1, and calreticulin) and an increase in proapoptotic genes (Bim, Bid, Nix, Gadd34, and Pdia2). Therefore, Tcf19 is necessary for both proliferation and survival and is a novel regulator of these pathways.
authors.affiliation: Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin, Madison, Wisconsin;
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Krautkramer
authors.forename: Amelia K
authors.initials: AK
authors.lastname: Linnemann
authors.forename: Danielle A
authors.initials: DA
authors.lastname: Fontaine
authors.forename: Amy L
authors.initials: AL
authors.lastname: Whillock
authors.forename: Ted W
authors.initials: TW
authors.lastname: Harris
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Schleis
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Truchan
authors.forename: Leilani
authors.initials: L
authors.lastname: Marty-Santos
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Lavine
authors.forename: Ondine
authors.initials: O
authors.lastname: Cleaver
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Kimple
authors.forename: Dawn Belt
authors.initials: DB
authors.lastname: Davis
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000502:physiology; D003920:Diabetes Mellitus / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D059865:Endoplasmic Reticulum Stress / Q000502:physiology*; D006801:Humans; D017403:In Situ Hybridization; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012313:RNA / Q000737:chemistry / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
chemical_list: D034741:RNA, Small Interfering; C098583:TCF19 protein, human; D014157:Transcription Factors; D012313:RNA
keywords: apoptosis; diabetes; endoplasmic reticulum stress; islet; proliferation; transcription; transcription factor 19; β-cell