过氧化物酶是普遍存在的硫醇依赖性过氧化物酶,在原核细胞和真核生物中代表着主要的抗氧化防御。在六种脊椎动物过氧化物氧化还原蛋白亚型中,过氧化物酶5(PRDX5)似乎是一种特殊的过氧化物酶,显示不同的催化机制,以及更广泛的底物特异性和亚细胞分布。此外,几个进化的特点,例如在某些物种中失去亚细胞靶向,已经报道了这种酶。
2-cysPRDXs(PRDX1-5)的Western印迹分析未能鉴定鸡组织匀浆中的PRDX5同工型。此后,通过PRDX5直系同源物的计算机模拟分析,我们继续证明PRDX5基因在羊膜进化枝的所有分支中都是保守的,除了aves。对鸟类基因组序列和表达的标签序列的进一步研究证实了该基因的消失,虽然TRMT112是一个靠近PRDX5基因5末端的基因,是保守的。最后,使用卵内电穿孔过度表达人类PRDX5的长短形式,我们表明,虽然基因在鸟类中丢失了,人PRDX5的亚细胞靶向在雏鸡中是保守的。
进一步增加了这种酶的独特性,这项研究报告了支持PRDX5丢失的证据。深入分析显示,由于PRDX5似乎在非禽类羊膜中被保存,因此这种缺失对鸟类来说是适当的。最后,利用卵内电穿孔技术,我们验证了人PRDX5在鸡胚胎中的亚细胞靶向性,并提出了这种功能获得模型作为体内研究PRDX5功能的有效方法.
Peroxiredoxins are ubiquitous thiol-dependent peroxidases that represent a major antioxidant defense in both prokaryotic cells and eukaryotic organisms. Among the six vertebrate peroxiredoxin isoforms, peroxiredoxin-5 (PRDX5) appears to be a particular peroxiredoxin, displaying a different catalytic mechanism, as well as a wider substrate specificity and subcellular distribution. In addition, several evolutionary peculiarities, such as loss of subcellular targeting in certain species, have been reported for this enzyme.
Western blotting analyses of 2-cys PRDXs (PRDX1-5) failed to identify the PRDX5 isoform in chicken tissue homogenates. Thereafter, via in silico analysis of PRDX5 orthologs, we went on to show that the PRDX5 gene is conserved in all branches of the amniotes clade, with the exception of aves. Further investigation of bird genomic sequences and expressed tag sequences confirmed the disappearance of the gene, though TRMT112, a gene located closely to the 5\' extremity of the PRDX5 gene, is conserved. Finally, using in ovo electroporation to overexpress the long and short forms of human PRDX5, we showed that, though the gene is lost in birds, subcellular targeting of human PRDX5 is conserved in the chick.
Further adding to the distinctiveness of this enzyme, this study
reports converging evidence supporting loss of PRDX5 in aves. In-depth analysis revealed that this absence is proper to birds as PRDX5 appears to be conserved in non-avian amniotes. Finally, taking advantage of the in ovo electroporation technique, we validate the subcellular targeting of human PRDX5 in the chick embryo and bring forward this gain-of-function model as a potent way to study PRDX5 functions in vivo.