Silva Gerda Cristal Villalba, Borsatto Taciane, Schwartz Ida Vanessa Doederlein, Sperb-Ludwig Fernanda
Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brazil.
Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Laboratório BRAIN, Porto Alegre, RS, Brazil.
Genet Mol Biol. 2022 Feb 14;45(1):e20200432. doi: 10.1590/1678-4685-GMB-2020-0432. eCollection 2022.
Reduced biotinidase activity is associated with a spectrum of deficiency ranging from total deficiency to heterozygous levels, a finding that is not always explained by the pathogenic variants observed in the BTD gene. The investigation of miRNAs, regulatory elements and variants in the 3'UTR region may present relevance in understanding the genotype-phenotype association. The aims of the study were to characterize the regulatory elements of the 3'UTR of the BTD gene and identify variants and miRNAs which may explain the discrepancies observed between genotype and biochemical phenotype. We evaluated 92 individuals with reduced biotinidase activity (level of heterozygotes = 33, borderline = 35, partial DB = 20 or total DB= 4) with previously determined BTD genotype. The 3'UTR of the BTD gene was Sanger sequenced. In silico analysis was performed to identify miRNAs and regulatory elements. No variants were found in the 3'UTR. We found 97 possible miRNAs associated with the BTD gene, 49 predicted miRNAs involved in the alanine, biotin, citrate and pyruvate metabolic pathways and 5 genes involved in biotin metabolism. Six AU-rich elements were found. Our data suggest variants in the 3'UTR of BTD do not explain the genotype-phenotype discrepancies found in Brazilian individuals with reduced biotinidase.
生物素酶活性降低与一系列缺乏情况相关，范围从完全缺乏到杂合子水平，这一发现并不总是能由在BTD基因中观察到的致病变异来解释。对3'UTR区域中的微小RNA（miRNA）、调控元件和变异的研究可能与理解基因型-表型关联相关。本研究的目的是表征BTD基因3'UTR的调控元件，并鉴定可能解释在基因型和生化表型之间观察到的差异的变异和miRNA。我们评估了92名生物素酶活性降低的个体（杂合子水平 = 33，临界水平 = 35，部分生物素酶缺乏 = 20或完全生物素酶缺乏 = 4），其BTD基因型先前已确定。对BTD基因的3'UTR进行了桑格测序。进行了计算机分析以鉴定miRNA和调控元件。在3'UTR中未发现变异。我们发现了97种可能与BTD基因相关的miRNA，49种预测参与丙氨酸、生物素、柠檬酸盐和丙酮酸代谢途径的miRNA，以及5个参与生物素代谢的基因。发现了六个富含AU的元件。我们的数据表明，BTD基因3'UTR中的变异并不能解释在巴西生物素酶活性降低个体中发现的基因型-表型差异。
