Davis J M, Clarke H R, Bradshaw H D, Gordon M P
U.S. Forest Service, North Central Forest Experiment Station, Rhinelander, WI 54501.
Plant Mol Biol. 1991 Oct;17(4):631-9. doi: 10.1007/BF00037049.
Poplar trees have at least two different chitinase genes, win6 and win8, which are systemically wound-inducible and belong to multigene families [Proc Natl Acad Sci USA 86: 7895-7899]. On one genomic clone that we have partially sequenced, there are three win6 genes which are transcriptionally oriented in the same direction. Between two of the win6 genes is a gene that we have designated chitinase X (chiX), which appears to be a pseudogene belonging to a multigene family distinct from win6 and win8. The win6 and chiX genes we have sequenced contain two AT-rich introns that correspond in location to those in a basic chitinase gene from tobacco. The predicted Win6 proteins have a putative signal peptide, a cysteine-rich 'hevein' domain, a hinge region, and a catalytic domain as described in Shinshi et al. [Plant Mol Biol 14: 357-368]. The predicted Win8 protein, by contrast, completely lacks a hinge region. Both Win6 and Win8 are expected to be highly acidic (with a calculated net charge of -15 to -17), whereas ChiX proteins are likely to be basic. Based on an inferred phylogeny, the catalytic domain of ChiX is more closely related to the basic chitinases of herbaceous plants than are either Win6 or Win8.
杨树至少有两个不同的几丁质酶基因，即win6和win8，它们可被系统性创伤诱导，属于多基因家族[《美国国家科学院院刊》86: 7895 - 7899]。在我们已部分测序的一个基因组克隆上，有三个win6基因，它们的转录方向相同。在其中两个win6基因之间有一个我们命名为几丁质酶X（chiX）的基因，它似乎是一个假基因，属于一个与win6和win8不同的多基因家族。我们测序的win6和chiX基因含有两个富含AT的内含子，其位置与烟草一个基本几丁质酶基因中的内含子相对应。预测的Win6蛋白具有一个假定的信号肽、一个富含半胱氨酸的“橡胶素”结构域、一个铰链区以及如Shinshi等人[《植物分子生物学》14: 357 - 368]所述的催化结构域。相比之下，预测的Win8蛋白完全缺乏铰链区。预计Win6和Win8都呈高酸性（计算得到的净电荷为 - 15至 - 17），而ChiX蛋白可能呈碱性。基于推断的系统发育，ChiX的催化结构域与草本植物的碱性几丁质酶的关系比Win6或Win8与它们的关系更为密切。
