The evolutionary origin of animal cellulose synthase
The evolutionary origin of animal cellulose synthase
复制标题
DOI：
10.1007/s00427-003-0379-8
复制
发表时间：
2004-02-01
影响因子：
2.4
通讯作者：
Satoh, N
中科院分区：
文献类型：
--
作者：
Nakashima, K;Yamada, L;Satoh, N
尾索动物是唯一产生纤维素的动物，纤维素是一种主要存在于植物、藻类和细菌细胞的细胞外基质中的多糖。在这里，我们报告了玻璃海鞘纤维素合成酶，这是多酶复合物的核心催化亚基纤维素生物合成发生同源。玻璃海鞘纤维素合酶基因Ci-CesA是纤维素合酶结构域和纤维素酶（纤维素水解酶）结构域的融合体。这两个领域在公共数据库中没有动物同源物。利用这种融合的非典型基因，我们提供了一个可能的横向转移的细菌纤维素合成酶基因的证据到尿索动物谱系。根据化石记录，这种纤维素合成酶基因的横向获得可能发生在5.3亿年前现存的尾索动物的最后一个共同祖先身上。整体原位杂交结果显示，C1-CesA在C. C-CesA的表达模式与体内观察到的纤维素合成在时空上一致。我们在这里提出，urochordates可能使用横向收购的“同源”基因的纤维素合成的类似过程。
Urochordates are the only animals that produce cellulose, a polysaccharide existing primarily in the extracellular matrices of plant, algal, and bacterial cells. Here we report a Ciona intestinalis homolog of cellulose synthase, which is the core catalytic subunit of multi-enzyme complexes where cellulose biosynthesis occurs. The Ciona cellulose synthase gene, Ci-CesA, is a fusion of a cellulose synthase domain and a cellulase (cellulose-hydrolyzing enzyme) domain. Both the domains have no animal homologs in public databases. Exploiting this fusion of atypical genes, we provided evidence of a likely lateral transfer of a bacterial cellulose synthase gene into the urochordate lineage. According to fossil records, this likely lateral acquisition of the cellulose synthase gene may have occurred in the last common ancestor of extant urochordates more than 530 million years ago. Whole-mount in situ hybridization analysis revealed the expression of Ci-CesA in C. intestinalis embryos, and the expression pattern of Ci-CesA was spatiotemporally consistent with observed cellulose synthesis in vivo. We propose here that urochordates may use a laterally acquired "homologous" gene for an analogous process of cellulose synthesis.