Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
BMC Genomics. 2010 Apr 30;11:276. doi: 10.1186/1471-2164-11-276.
A recent comparative genomic analysis tentatively identified roughly 40 orthologous groups of C2H2 Zinc-finger proteins that are well conserved in "bilaterians" (i.e. worms, flies, and humans). Here we extend that analysis to include a second arthropod genome from the crustacean, Daphnia pulex.
Most of the 40 orthologous groups of C2H2 zinc-finger proteins are represented by just one or two proteins within each of the previously surveyed species. Likewise, Daphnia were found to possess a similar number of orthologs for all of these small orthology groups. In contrast, the number of Sp/KLF homologs tends to be greater and to vary between species. Like the corresponding mammalian Sp/KLF proteins, most of the Drosophila and Daphnia homologs can be placed into one of three sub-groups: Class I-III. Daphnia were found to have three Class I proteins that roughly correspond to their Drosophila counterparts, dSP1, btd, CG5669, and three Class II proteins that roughly correspond to Luna, CG12029, CG9895. However, Daphnia have four additional KLF-Class II proteins that are most similar to the vertebrate KLF1/2/4 proteins, a subset not found in Drosophila. Two of these four proteins are encoded by genes linked in tandem. Daphnia also have three KLF-Class III members, one more than Drosophila. One of these is a likely Bteb2 homolog, while the other two correspond to Cabot and KLF13, a vertebrate homolog of Cabot.
Consistent with their likely roles as fundamental determinants of bilaterian form and function, most of the 40 groups of C2H2 zinc-finger proteins are conserved in kind and number in Daphnia. However, the KLF family includes several additional genes that are most similar to genes present in vertebrates but missing in Drosophila.
最近的比较基因组分析初步确定了大约 40 个保守的“两侧对称动物”（即线虫、蝇类和人类）中 C2H2 锌指蛋白的直系同源物。在这里，我们将该分析扩展到包括第二个节肢动物基因组，即溞属甲壳类动物。
在之前调查的物种中，大多数 C2H2 锌指蛋白的 40 个直系同源物组仅由一个或两个蛋白代表。同样，溞属也拥有所有这些小直系同源物组的类似数量的同源物。相比之下，Sp/KLF 同源物的数量往往更大，并且在物种之间存在差异。与相应的哺乳动物 Sp/KLF 蛋白一样，大多数果蝇和溞属的同源物可以归入三个亚组之一：I-III 类。溞属有三个 I 类蛋白，大致对应于它们的果蝇对应物，dSP1、btd 和 CG5669，还有三个 II 类蛋白，大致对应于 Luna、CG12029 和 CG9895。然而，溞属有四个额外的 KLF-Class II 蛋白，它们与脊椎动物 KLF1/2/4 蛋白最为相似，这在果蝇中没有发现。这四个蛋白中的两个由串联的基因编码。溞属也有三个 KLF-Class III 成员，比果蝇多一个。其中一个可能是 Bteb2 同源物，而另外两个则对应于 Cabot 和 KLF13，这是 Cabot 的脊椎动物同源物。
与它们作为两侧对称动物形态和功能的基本决定因素的作用一致，大多数 40 个 C2H2 锌指蛋白组在溞属中以相同的种类和数量保守。然而，KLF 家族包括几个与脊椎动物相似但在果蝇中缺失的额外基因。
