The Brassica MIP-MOD gene encodes a functional water channel that is expressed in the stigma epidermis
The Brassica MIP-MOD gene encodes a functional water channel that is expressed in the stigma epidermis
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DOI：
10.1023/a:1006428007826
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发表时间：
2001-01-01
影响因子：
5.1
通讯作者：
Nasrallah, J
中科院分区：
文献类型：
--
作者：
Dixit, R;Rizzo, C;Nasrallah, J
在十字花科植物中，柱头差异调节花粉粒水合作用的能力，取决于花粉是否被认为是相容的或不相容的，代表了授粉的一个关键阶段。我们最近分析了芸苔属的mod突变，这导致自交不亲和反应的崩溃，导致分离出与MOD基因座连锁的基因，该基因在mod突变体中以低水平表达。该基因被预测为编码质膜定位的水通道蛋白样蛋白，并已被指定为MIP-MOD。我们利用报告基因分析表明，MIP-MOD启动子是活跃的，在芸苔属乳头状细胞以及在一些营养组织。所编码的蛋白质也可能是质膜定位的基础上观察到的所有质膜内在的水通道蛋白样蛋白质在芸苔属植物叶片中富集质膜组分。MIP-MOD蛋白导致非洲爪蟾卵母细胞的渗透水渗透性的低但可测量的增强，因此代表功能性水通道蛋白。这些结果与MIP-MOD参与调节柱头表皮细胞膜水分运输的观点一致。
In crucifers, the ability of the stigma to differentially modulate hydration of pollen grains, depending on whether the pollen is recognized to be compatible or incompatible, represents a crucial stage in pollination. Our recent analysis of the mod mutation of Brassica, which results in a breakdown of the self-incompatibility response, led to the isolation of a gene linked to the MOD locus which is expressed at low levels in mod mutants. The gene is predicted to encode a plasma membrane-localized aquaporin-like protein and has been designated MIP-MOD. We utilized reporter gene analysis to demonstrate that the MIP-MOD promoter is active in Brassica papillar cells as well as in some vegetative tissues. The encoded protein is also likely to be plasma membrane-localized based on the observation that all plasma membrane-intrinsic aquaporin-like proteins in Brassica leaves are enriched in plasma membrane fractions. The MIP-MOD protein results in a low but measurable enhancement in osmotic water permeability of Xenopus oocytes and hence represents a functional aquaporin. The results are consistent with the notion that MIP-MOD is involved in the regulation of water transport across the stigma epidermal cell membrane.