RESUMO
The adrenal 11 beta-hydroxylase is a mitochondrial P450 enzyme encoded by the CYP11B1 gene, which is situated on chromosome 8q22 in tandem with the gene for aldosterone synthase (CYP11B2). Deficiency of 11 beta-hydroxylase results in the inability to convert 11-deoxycortisol to cortisol and accounts for 5-8% of cases of congenital adrenal hyperplasia. In the following study the CYP11B1 genes from eight individuals with 11 beta-hydroxylase deficiency were screened for mutations using single strand conformation polymorphism (SSCP) analysis. Sequence analysis of variant exons revealed a 28 bp deletion and a 5 bp duplication exon 2 and five missense mutations, G267R, G267D, Q356X, R427H and C494F, distributed throughout the gene. One of these mutations, G267R, and a G to A transversion at the third nucleotide position of codon 318 occur at the +1 position of the splice donor sites. Mutations were neither the result of gene conversion nor nonhomologous recombination between the two closely related CYP11B genes.
Assuntos
Citocromo P-450 CYP11B2/genética , Genes , Mutação , Polimorfismo Conformacional de Fita Simples , Sequência de Bases , Pré-Escolar , Éxons , Feminino , Deleção de Genes , Humanos , Lactente , Recém-Nascido , Masculino , Dados de Sequência Molecular , Família Multigênica , Sondas de Oligonucleotídeos/genéticaRESUMO
The minimal promoter of rat thyroglobulin (TG) gene (168 bp) was fused with bacterial chloramphenicol acetyltransferase (CAT) gene, and transgenic mice carrying the TGCAT gene were produced. The minimal promoter is sufficient for thyroid-specific and hormone-dependent expression of TGCAT in transgenic mice. Deletion of a region between -128 and -92 bp (TGII), which is not required for the expression of TGCAT in transient expression assays but whose sequence is most extensively conserved among different species, appears to decrease frequency of the expression of TGCAT in transgenic mice. However, the same deletion apparently has no significant effect on TG promoter activity in stably transformed rat FRTL-5 cells.
Assuntos
Regulação da Expressão Gênica , Genes Sintéticos , Regiões Promotoras Genéticas , Proteínas Recombinantes de Fusão/biossíntese , Tireoglobulina/genética , Glândula Tireoide/metabolismo , Animais , Proteínas de Bactérias/genética , Sequência de Bases , Bovinos , Células Cultivadas , Cloranfenicol O-Acetiltransferase/biossíntese , Cloranfenicol O-Acetiltransferase/genética , Vetores Genéticos , Humanos , Camundongos , Camundongos Transgênicos , Dados de Sequência Molecular , Especificidade de Órgãos , Plasmídeos , Ratos , Proteínas Recombinantes de Fusão/genética , Sequências Reguladoras de Ácido Nucleico , Deleção de Sequência , Homologia de Sequência do Ácido Nucleico , Especificidade da Espécie , Tireoglobulina/biossíntese , Glândula Tireoide/citologia , Tireotropina/fisiologiaRESUMO
Four sequence variants in the 11 beta-hydroxylase (CYP11B1) gene are reported. One of the sequence changes occurs in exon 1 and is in linkage disequilibrium with a second variant in intron 3. The other two changes occur at adjacent nucleotides in intron 1. The finding of easily demonstrable, intragenic variants will be beneficial to the study of the role of the CYP11B1 and the adjacent aldosterone synthase (CYP11B2) gene in hypertensive disease.
Assuntos
Polimorfismo Genético , Esteroide 11-beta-Hidroxilase/genética , Alelos , Enzimas de Restrição do DNA , Éxons , Frequência do Gene , Humanos , Íntrons , Desequilíbrio de LigaçãoRESUMO
Major histocompatibility complex (MHC) class I-deficient cell lines were used to demonstrate that the MHC class II transactivator (CIITA) can induce surface expression of MHC class I molecules. CIITA induces the promoter of MHC class I heavy chain genes. The site alpha DNA element is the target for CIITA-induced transactivation of class I. In addition, interferon-gamma (IFNgamma)-induced MHC class I expression also requires an intact site alpha. The G3A cell line, which is defective in CIITA induction, does not induce MHC class I antigen and promoter in response to IFNgamma. Trans-dominant-negative forms of CIITA reduce class I MHC promoter function and surface antigen expression. Collectively, these data argue that CIITA has a role in class I MHC gene induction.