CELL SURFACE GLYCOPROTEINS AND PLACE DEPENDENT SUPPRESSION OF CELL PROLIFERATION

阿拉伯半乳糖蛋白(AGPs)由一个羟基脯氨酸大家族组成。 含有与植物细胞表面相关的糖蛋白，既有 质膜和细胞外基质。他们拥有的证据 在植物生长和发育中的重要作用开始积累 以加速的速度。在其他事情中，他们被牵连为 身份的决定因素和作为形态调节分子。我们有 获得的实验证据表明，形态调节作用对 AGPS可以从它们产生和/或维持 处于抑制状态的潜在增殖细胞。AGPS展品 在我们工作的工厂中，浮力密度的范围从1.55到1.73 和.。我们发现表面结合的AGP组分具有浮力密度 在膨胀裸子体中约为1.62，在莴苣中约为1.70。 V Romana茎髓中的细胞增殖通常受到抑制， 不存在于细胞增殖实验中的植物/组织中 “去压抑”。我们将变得“释放”的AGP部分定性为 作为HBD-(高浮力密度)AGP和那些保持LBD-结合的AGP- (低浮力密度)AGPS。不同的密度等级很容易 用CSCL梯度分析分离总AGP提取物。我们建议 分离和比较HBD-和LBD-的化学成分 膨胀棉和紫花苜蓿的AGPS，看看有没有什么 除了糖基化程度不同的密度 上课。此外，我们还将比较膨胀棉和黄瓜的HBD-AGPs。 看看我们能不能找到一些共同的、保守的特征(S) 类，其中绑定属性的更改与受抑制的与 解除对细胞增殖的抑制。合并的、平行的比较 地钱配子体和生菜茎的化学成分分析 组织有望提供线索，说明某些病毒的存在是如何 细胞表面的HBD-AGPs有助于维持潜在的增殖 处于抑制状态的单元格。

Arabinogalactan proteins (AGPs) comprise a large family of hydroxyproline- containing glycoproteins associated with plant cell surfaces, both the plasmalemma and the extra-cellular matrix. Evidence for their having important roles in plant growth and development is beginning to accumulate at an accelerating rate. Among other things, they have been implicated as determinants of identity and as morphoregulatory molecules. We have obtained experimental evidence that a morphoregulatory role for certain AGPs may derive from their capacity to bring about and/or maintain potentially proliferating cells in a state of suppression. AGPs exhibit a range in buoyant densities from 1.55-1.73 in the plants we are working with. We found that surface-bound AGP fractions with buoyant densities about l.62 in Gymnocolea inflata gametophytes and l.70 in Lactuca sativa v Romana stem pith in which cell proliferation is normally suppressed, are absent from plants/tissues in which cell proliferation is experimentally "desuppressed". We characterize the AGP fractions that become "released" as HBD- (high buoyant density) AGPs and those that remain bound as LBD- (low buoyant density) AGPs. The different density classes are readily separated in total AGP extracts using CsCl gradient analysis. We propose to separate and compare the chemical compositions of the HBD- with LBD- AGPs of G. inflata as well as of L. sativa to see if there is something other than the degree of glycosylation that distinguishes the density classes. We will also compare HBD-AGPs of G. inflata with those of L. sativa to see if we can find some common, conserved feature(s) in this class in which binding properties change correlated with suppressed vs. desuppressed cell proliferation. The combined, parallel comparative chemical analysis of the liverwort gametophytes and the lettuce stem tissue are expected to provide a clue as to how the presence of certain HBD-AGPs at the cell surface helps maintain potentially proliferating cells in a suppressed state.