title: NF-YA splice variants have different roles on muscle differentiation.
abstract: The heterotrimeric CCAAT-binding factor NF-Y controls the expression of a multitude of genes involved in cell cycle progression. NF-YA is present in two alternatively spliced isoforms, NF-YAs and NF-YAl, differing in 28 aminoacids in the N-terminal Q-rich activation domain. NF-YAs has been identified as a regulator of stemness and proliferation in mouse embryonic cells (mESCs) and human hematopoietic stem cells (hHSCs), whereas the role of NF-YAl is not clear. In the muscle system, NF-YA expression is observed in proliferating cells, but barely detectable in terminally differentiated cells in vitro and adult skeletal muscle in vivo. Here, we show that NF-YA inactivation in mouse myoblasts impairs both proliferation and differentiation. The overexpression of the two NF-YA isoforms differentially affects myoblasts fate: NF-YAs enhance cell proliferation, while NF-YAl boosts differentiation. The molecular mechanisms were investigated by expression profilings, detailing the opposite programs of the two isoforms. Bioinformatic analysis of the regulated promoters failed to detect a significant presence of CCAAT boxes in the regulated genes. NF-YAl activates directly Mef2D, Six genes, and p57kip2 (Cdkn1c), and indirectly the myogenic regulatory factors (MRFs). Specifically, Cdkn1c activation is induced by NF-Y binding to its CCAAT promoter and by reducing the expression of the lncRNA Kcnq1ot1, a negative regulator of Cdkn1c transcription. Overall, our results indicate that NF-YA alternative splicing is an influential muscle cell determinant, through direct regulation of selected cell cycle blocking genes, and, directly and indirectly, of muscle-specific transcription factors.
authors.affiliation: Dipartimento di Scienze della Vita, Università degli Studi di Modena e Reggio Emilia, Via Campi 213/D e Via Campi 287, Modena, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Basile
authors.affiliation: Dipartimento di Scienze della Vita, Università degli Studi di Modena e Reggio Emilia, Via Campi 213/D, 41125 Modena, Italy.
authors.forename: Fiorenza
authors.initials: F
authors.lastname: Baruffaldi
authors.affiliation: Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
authors.forename: Diletta
authors.initials: D
authors.lastname: Dolfini
authors.affiliation: Dipartimento di Scienze della Vita, Università degli Studi di Modena e Reggio Emilia, Via Campi 213/D e Via Campi 287, Modena, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Belluti
authors.affiliation: Dipartimento di Scienze della Vita, Università degli Studi di Modena e Reggio Emilia, Via Campi 213/D e Via Campi 287, Modena, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Benatti
authors.affiliation: Dipartimento di Scienze della Vita, Università degli Studi di Modena e Reggio Emilia, Via Campi 213/D e Via Campi 287, Modena, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Ricci
authors.affiliation: Centro di Ricerche Genomiche, Dipartimento di Scienze della Vita, Università degli Studi di Modena e Reggio Emilia, Via Campi 287, 41125 Modena, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Artusi
authors.affiliation: Centro di Ricerche Genomiche, Dipartimento di Scienze della Vita, Università degli Studi di Modena e Reggio Emilia, Via Campi 287, 41125 Modena, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Tagliafico
authors.affiliation: Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Mantovani
authors.affiliation: Dipartimento di Scienze della Vita, Università degli Studi di Modena e Reggio Emilia, Via Campi 213/D, 41125 Modena, Italy. Electronic address: susanna.molinari@unimore.it.
authors.forename: Susanna
authors.initials: S
authors.lastname: Molinari
authors.affiliation: Dipartimento di Scienze della Vita, Università degli Studi di Modena e Reggio Emilia, Via Campi 213/D e Via Campi 287, Modena, Italy. Electronic address: cimbriano@unimo.it.
authors.forename: Carol
authors.initials: C
authors.lastname: Imbriano
mesh_terms: D000818:Animals; D023081:CCAAT-Binding Factor / Q000096:biosynthesis / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics*; D049109:Cell Proliferation / Q000235:genetics; D019926:Cyclin B / Q000096:biosynthesis; D018507:Gene Expression Regulation, Developmental; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D051379:Mice; D024510:Muscle Development / Q000235:genetics*; D018482:Muscle, Skeletal / Q000254:growth & development*; D032446:Myoblasts / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000235:genetics*; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics
chemical_list: D023081:CCAAT-Binding Factor; D019926:Cyclin B; C492061:NFYA protein, human; D020033:Protein Isoforms; D014157:Transcription Factors
keywords: Alternative splicing; Gene expression; Muscle differentiation; NF-Y; Transcription factor