The early evolution of the phosphagen kinases - Insights from choanoflagellate and poriferan arginine kinases
The early evolution of the phosphagen kinases - Insights from choanoflagellate and poriferan arginine kinases
复制标题
DOI：
10.1007/s00239-007-9058-0
复制
发表时间：
2008-01-01
影响因子：
3.9
通讯作者：
Ellington, W. Ross
中科院分区：
文献类型：
--
作者：
Conejo, Maria;Bertin, Matt;Ellington, W. Ross
精氨酸激酶（AK）是磷酸基转移酶大家族的一员，称为磷酸根（胍）激酶。AKs存在于某些原生动物、海绵动物、刺胞动物以及光栖动物和外生动物的原生口动物中。另一种磷酸激酶，肌酸激酶（CK），存在于海绵、刺胞动物、后口动物和原口动物中，但似乎不存在于原生动物中。为了研究磷脂激酶的早期进化，我们扩增了三种鞭毛虫、六根海绵体海绵Aphrocallistes beatrix和demosponge Suberites fuscus和Microciona prolifera的ak的cdna。系统发育分析结果显示，长鞭毛单胞菌AK与玻璃海绵Aphrocallistes AK聚集在一起，是一个更大的AK集群的一部分，该集群包含了来自无鞭毛单胞菌亚种和微孔单胞菌以及基础和原生无脊椎动物的AK。相比之下，来自细叶参和卵形单胞菌的AK形成一个不同于所有其他AK序列的独特簇。用blastn对最近公布的短尾霉基因组数据库进行检索，发现该物种有三个独特的AK基因，其中一个与短尾霉的cDNA几乎相同，另外两个与C. gracilis和M. ovata AK非常相似。三种不同的AK基因可能存在于鞭藻中。其中两个AK与ck和海绵AK具有广泛的相似性。先前的研究表明，CK是从一个类似ak的祖先进化而来的，早于海绵的分化。目前的结果提供了证据，表明导致CK谱系的初始基因复制事件可能发生在鞭毛类和动物谱系分化之前。
Arginine kinase (AK) is a member of a large family of phosphoryl transfer enzymes called phosphagen (guanidino) kinases. AKs are present in certain protozoans, sponges, cnidarians, and both lophotrochozoan and ecdysozoan protostomes. Another phosphagen kinase, creatine kinase (CK), is found in sponges, cnidarians, and both deuterostome and protostome groups but does not appear to be present in protozoans. To probe the early evolution of phosphagen kinases, we have amplified the cDNAs for AKs from three choanoflagellates and from the hexactinellid sponge Aphrocallistes beatrix and the demosponges Suberites fuscus and Microciona prolifera. Phylogenetic analysis using maximum likelihood of these choanoflagellate and sponge AKs with other AK sequences revealed that the AK from the choanoflagellate Monosiga brevicollis clusters with the AK from the glass sponge Aphrocallistes and is part of a larger cluster containing AKs from the demosponges Suberites and Microciona as well as basal and protostome invertebrates. In contrast, AKs from Codonosiga gracilis and Monosiga ovata form a distinct cluster apart from all other AK sequences. tBLASTn searches of the recently released M. brevicollis genome database showed that this species has three unique AK genes-one virtually identical to the M. brevicollis cDNA and the other two showing great similarity to C. gracilis and M. ovata AKs. Three distinct AK genes are likely present in choanoflagellates. Two of these AKs display extensive similarity to both CKs and an AK from sponges. Previous work has shown CK evolved from an AK-like ancestor prior to the divergence of sponges. The present results provide evidence suggesting that the initial gene duplication event(s) leading to the CK lineage may have occurred before the divergence of the choanoflagellate and animal lineages.