RESUMO
3-M syndrome is a primordial growth disorder caused by mutations in CUL7, OBSL1 or CCDC8. 3-M patients typically have a modest response to GH treatment, but the mechanism is unknown. Our aim was to screen 13 clinically identified 3-M families for mutations, define the status of the GH-IGF axis in 3-M children and using fibroblast cell lines assess signalling responses to GH or IGF1. Eleven CUL7, three OBSL1 and one CCDC8 mutations in nine, three and one families respectively were identified, those with CUL7 mutations being significantly shorter than those with OBSL1 or CCDC8 mutations. The majority of 3-M patients tested had normal peak serum GH and normal/low IGF1. While the generation of IGF binding proteins by 3-M cells was dysregulated, activation of STAT5b and MAPK in response to GH was normal in CUL7(-/-) cells but reduced in OBSL1(-/-) and CCDC8(-/-) cells compared with controls. Activation of AKT to IGF1 was reduced in CUL7(-/-) and OBSL1(-/-) cells at 5âmin post-stimulation but normal in CCDC8(-/-) cells. The prevalence of 3-M mutations was 69% CUL7, 23% OBSL1 and 8% CCDC8. The GH-IGF axis evaluation could reflect a degree of GH resistance and/or IGF1 resistance. This is consistent with the signalling data in which the CUL7(-/-) cells showed impaired IGF1 signalling, CCDC8(-/-) cells showed impaired GH signalling and the OBSL1(-/-) cells showed impairment in both pathways. Dysregulation of the GH-IGF-IGF binding protein axis is a feature of 3-M syndrome.
Assuntos
Proteínas de Transporte/genética , Proteínas Culina/genética , Proteínas do Citoesqueleto/genética , Nanismo/genética , Nanismo/metabolismo , Hipotonia Muscular/genética , Hipotonia Muscular/metabolismo , Criança , Pré-Escolar , Nanismo/sangue , Nanismo/patologia , Feminino , Hormônio do Crescimento/sangue , Humanos , Lactente , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Hipotonia Muscular/sangue , Hipotonia Muscular/patologia , Mutação , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Coluna Vertebral/anormalidades , Coluna Vertebral/metabolismo , Coluna Vertebral/patologiaRESUMO
On the basis of comparative mapping between cattle/sheep and human for milk trait quantitative trait loci (QTL) on BTA3/OAR1, annexin A9 (ANXA9) and solute carrier family 27 (fatty acid transporter), member 3 (SLC27A3) were selected as candidate genes for fat content (FC) in sheep milk. Two other genes in the same region, cingulin (CGN) and acid phosphatase 6, lysophosphatidic (ACP6), were also considered. DNA fragments of 1931 and 2790 bp corresponding to ANXA9 and SLC27A3 respectively were isolated, and 14 and 6 single nucleotide polymorphisms (SNPs) respectively were found in each gene. ANXA9, SLC27A3, CGN and ACP6 were localized to chromosome 1 between INRA006 and AE57 by linkage mapping using the International Mapping Flock. Across-family analyses of a daughter design comprising 13 sire families revealed significant sire and SLC27A3 genotype-nested-within-sire effects for FC. Within-family analyses indicated significant regression coefficients for FC in four of six heterozygous sires. These results could reflect the existence of a QTL for FC linked to SLC27A3 in sheep.
Assuntos
Mapeamento Cromossômico , Cromossomos de Mamíferos , Leite , Locos de Características Quantitativas , Ovinos/genética , Animais , Genes , Genótipo , Leite/classificação , Polimorfismo de Nucleotídeo Único , Análise de Regressão , Homologia de Sequência de Aminoácidos , Ovinos/classificaçãoRESUMO
On the basis of fine mapping of a quantitative trait loci region of BTA3 for milk fat content, an examination of the comparative map between cattle and human indicates that the annexin 9 protein gene (ANXA9) and the fatty acid transport protein type 3 gene (SLC27A3) are two strong candidate genes. The objective of the present study is to isolate, map and characterize these genes and identify polymorphisms that could be further utilized in linkage or association studies. Furthermore, two new genes which are in the same region, cingulin protein gene (CGN) and lysophosphatidic acid phosphatase protein gene (ACP6) were studied. DNA fragments (869, 1778, 1933 and 2618 bp) corresponding to partial sequences of ACP6,CGN,ANXA9 and SLC27A3 genes were isolated. Direct sequencing of PCR products amplified from different cattle breeds revealed 1, 4, 4 and 2 SNPs for ACP6, CGN,ANXA9 and SLC27A3, respectively. For ANXA9 one SNP was located in exon 5 (A-->G 951) resulting in an amino acid change from histidine to arginine. Finally, ACP6,CGN,ANXA9 and SLC27A3 genes were located on chromosome 3 between ILSTS096 and BMS819 markers, in a region in which quantitative trait loci (QTL) for several milk traits have been described.