title: Functional characterization of a human POU1F1 mutation associated with isolated growth hormone deficiency: a novel etiology for IGHD.
abstract: POU1F1, a pituitary-specific POU-homeo domain transcription factor, plays an essential role in the specification of the somatotroph, lactotroph and thyrotroph lineages and in the activation of GH1, PRL and TSHβ transcription. Individuals with mutations in POU1F1 present with combined deficiency of GH, PRL and TSH. Here, we identified a heterozygous missense mutation with evidence of pathogenicity, at the POU1F1 locus, in a large family in which an isolated growth hormone deficiency segregates as an autosomal dominant trait. The corresponding p.Pro76Leu mutation maps to a conserved site within the POU1F1 transactivation domain. Bandshift assays revealed that the mutation alters wild-type POU1F1 binding to cognate sites within the hGH-LCR and hGH1 promoter, but not to sites within the PRL promoter, and it selectively increases binding affinity to sites within the hGH-LCR. Co-immunoprecipitation studies reveal that this substitution enhances interactions of POU1F1 with three of its cofactors, PITX1, LHX3a and ELK1, and that residue 76 plays a critical role in these interactions. The insertion of the mutation at the mouse Pou1f1 locus results in a dramatic loss of protein expression despite normal mRNA concentrations. Mice heterozygous for the p.Pro76Leu mutation were phenotypically normal while homozygotes demonstrated a dwarf phenotype. Overall, this study unveils the involvement of POU1F1 in dominantly inherited isolated GH deficiency and demonstrates a significant impact of the Pro76Leu mutation on DNA-binding activities, alterations in transactivating functions and interactions with cofactors. Our data further highlight difficulties in modeling human genetic disorders in the mouse despite apparent conservation of gene expression pathways and physiologic functions.
authors.affiliation: Inserm UMRS933, Hôpital Trousseau, Sorbonne Universités, UPMC Univ Paris, 26 Avenue du Dr Netter, Paris 75012, France, marie-laure.sobrier@inserm.fr.
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Sobrier
authors.affiliation: Department of Genetics.
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Tsai
authors.affiliation: Inserm UMRS933, Hôpital Trousseau, Sorbonne Universités, UPMC Univ Paris, 26 Avenue du Dr Netter, Paris 75012, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Pérez
authors.affiliation: Service de Génétique Clinique Pédiatrique, Hôpital d'enfants, CHU Nancy, Vandoeuvre-Lès-Nancy, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Leheup
authors.affiliation: Institut de Biologie Paris-Seine, Plateforme d'Intéractions Moléculaires Fr 3631, UPMC, Paris, France and.
authors.forename: Tahar
authors.initials: T
authors.lastname: Bouceba
authors.affiliation: Inserm UMRS933, Hôpital Trousseau, Sorbonne Universités, UPMC Univ Paris, 26 Avenue du Dr Netter, Paris 75012, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Duquesnoy
authors.affiliation: Service de Génétique et d'Embryologie Médicales, Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Copin
authors.affiliation: Department of Genetics.
authors.forename: Daria
authors.initials: D
authors.lastname: Sizova
authors.affiliation: Gastroenterology Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Penzo
authors.affiliation: Gastroenterology Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
authors.forename: Ben Z
authors.initials: BZ
authors.lastname: Stanger
authors.affiliation: Department of Genetics.
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Cooke
authors.affiliation: Department of Genetics.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Liebhaber
authors.affiliation: Inserm UMRS933, Hôpital Trousseau, Sorbonne Universités, UPMC Univ Paris, 26 Avenue du Dr Netter, Paris 75012, France, Service de Génétique et d'Embryologie Médicales, Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Paris, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Amselem
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D004393:Dwarfism, Pituitary / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005260:Female; D005786:Gene Expression Regulation; D005799:Genes, Dominant; D056426:Genetic Loci; D013006:Growth Hormone / Q000235:genetics / Q000378:metabolism; D006579:Heterozygote; D006801:Humans; D060850:LIM-Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D051761:Paired Box Transcription Factors / Q000235:genetics / Q000378:metabolism; D010375:Pedigree; D010902:Pituitary Gland / Q000378:metabolism / Q000473:pathology; D011388:Prolactin / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D019655:Quantitative Trait, Heritable; D015398:Signal Transduction; D050817:Transcription Factor Pit-1 / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D050807:ets-Domain Protein Elk-1 / Q000235:genetics / Q000378:metabolism
chemical_list: D013006:Growth Hormone; D060850:LIM-Homeodomain Proteins; D051761:Paired Box Transcription Factors; D011388:Prolactin; D050817:Transcription Factor Pit-1; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; C494112:ELK1 protein, human; C094898:Lhx3 protein; C494187:POU1F1 protein, human; C494185:Pou1f1 protein, mouse; C101485:homeobox protein PITX1