Smallwood M, Martin H, Knox J P
Centre for Plant Biochemistry and Biotechnology, University of Leeds, UK.
Planta. 1995;196(3):510-22. doi: 10.1007/BF00203651.
A monoclonal antibody, LM1, has been derived that has a high affinity for an epitope of hydroxyproline-rich glycoproteins (HRGPs). In suspension-cultured rice (Oryza sativa L.) cells the epitope is carried by three major proteins with different biochemical properties. The most abundant is the 95-kDa extracellular rice extensin, a threonine- and hydroxyproline-rich glycoprotein (THRGP) occurring in the cell wall and secreted into the medium. This THRGP can be selectively oxidatively cross-linked in the presence of hydrogen peroxide and an endogenous peroxidase with the result that it does not enter a protein gel. A second polypeptide with the LM1 epitope (180 kDa), also occurring in the suspension-cultured cells and medium, is not oxidatively cross-linked. Three further polypeptides (52, 65 and 110 kDa) with the characteristics of hydrophobic proteins of the plasma-membrane also carry the LM1 epitope as determined by immuno-blotting of detergent/aqueous partitions of a plasma-membrane preparation and immuno-fluorescence studies with rice protoplasts. At the rice root apex the LM1 epitope is carried by four glycoproteins and is developmentally regulated. The major locations of the epitope are at the surface of cells associated with the developing protoxylem and metaxylem in the stele, the longitudinal radial walls of epidermal cells and a sheath-like structure at the surface of the root apex.
已获得一种单克隆抗体LM1，它对富含羟脯氨酸的糖蛋白（HRGPs）的一个表位具有高亲和力。在悬浮培养的水稻（Oryza sativa L.）细胞中，该表位由三种具有不同生化特性的主要蛋白质携带。最丰富的是95 kDa的细胞外水稻伸展蛋白，它是一种富含苏氨酸和羟脯氨酸的糖蛋白（THRGP），存在于细胞壁中并分泌到培养基中。这种THRGP在过氧化氢和内源性过氧化物酶存在的情况下可以被选择性地氧化交联，结果是它不会进入蛋白质凝胶。另一种带有LM1表位的多肽（180 kDa），也存在于悬浮培养的细胞和培养基中，不会被氧化交联。通过对质膜制剂的去污剂/水相分配进行免疫印迹以及对水稻原生质体进行免疫荧光研究确定，另外三种具有质膜疏水蛋白特征的多肽（52、65和110 kDa）也携带LM1表位。在水稻根尖，LM1表位由四种糖蛋白携带，并且受到发育调控。该表位的主要位置在与中柱中正在发育的原生木质部和后生木质部相关的细胞表面、表皮细胞的纵向径向壁以及根尖表面的鞘状结构处。
