The phylogeny and evolution of deoxyribonuclease II: an enzyme essential for lysosomal DNA degradation.
The phylogeny and evolution of deoxyribonuclease II: an enzyme essential for lysosomal DNA degradation.
复制标题
脱氧核糖核酸酶 II 的系统发育和进化：溶酶体 DNA 降解所必需的酶。
DOI：
10.1016/j.ympev.2007.11.033
复制
发表时间：
2008
影响因子：
4.1
通讯作者：
Aguilera,RenatoJ
中科院分区：
文献类型：
--
作者：
Shpak,Max;Kugelman,JeffreyR;Varela-Ramirez,Armando;Aguilera,RenatoJ
脱氧核糖核酸酶II(DNase II)是一种在低pH条件下活性最高的内切酶，定位于高等真核生物的溶酶体中。这种酶的起源仍然存在争议，它的系统发育分布给它随后的进化史留下了许多悬而未决的问题。早期的研究记录了它在各种后生动物中的存在，以及在毛滴虫和毛滴虫中的存在，并异常地存在于单一细菌属(伯克霍尔德菌)中。这项研究利用各种生物的基因组搜索已知的DNaseII查询序列，以确定这种酶在细胞生命形式中的可能起始点。它完全不存在于任何其他细菌中，因此不太可能起源于原核生物。令人信服的证据表明，DNase II在草履虫等泡状动物、硅藻和水霉等异形体中存在，甚至在绿藻中也存在试探性匹配。明显的缺失包括红藻、植物、真菌和一些寄生生物。基于这种系统发育分布和真核关系的假设，最可能的解释是DNase II遭受了多次丢失。这种起源是有争议的，尽管它存在于毛滴虫中，也可能存在于其他进化基础的原生生物中，如直单胞菌，它有力地支持了这一假说，即DNA酶II是作为真核生物的一种拟态特征出现的。它可能与吞噬作用一起进化，特别是为了促进DNA降解和细菌营养。细胞内寄生虫、专性自养生物和腐生植物的吞噬功能丧失可解释许多真核生物谱系中的不同缺失。
Deoxyribonuclease II (DNase II) is an endonuclease with optimal activity at low pH, localized within the lysosomes of higher eukaryotes. The origin of this enzyme remains in dispute, and its phylogenetic distribution leaves many questions about its subsequent evolutionary history open. Earlier studies have documented its presence in various metazoans, as well as in Dictyostelium, Trichomonas and, anomalously, a single genus of bacteria (Burkholderia). This study makes use of searches of the genomes of various organisms against known DNase II query sequences, in order to determine the likely point of origin of this enzyme among cellular life forms. Its complete absence from any other bacteria makes prokaryotic origin unlikely. Convincing evidence exists for DNase II homologs in Alveolates such as Paramecium, Heterokonts such as diatoms and water molds, and even tentative matches in green algae. Apparent absences include red algae, plants, fungi, and a number of parasitic organisms. Based on this phylogenetic distribution and hypotheses of eukaryotic relationships, the most probable explanation is that DNase II has been subject to multiple losses. The point of origin is debatable, though its presence in Trichomonas and perhaps in other evolutionarily basal “Excavate” protists such as Reclinomonas, strongly support the hypothesis that DNase II arose as a plesiomorphic trait in eukaryotes. It probably evolved together with phagocytosis, specifically to facilitate DNA degradation and bacteriotrophy. The various absences in many eukaryotic lineages are accounted for by loss of phagotrophic function in intracellular parasites, in obligate autotrophs, and in saprophytes.