Heath I B, Gupta G, Bai S
Biology Department, York University, Toronto, Ontario, Canada.
Fungal Genet Biol. 2000 Jun;30(1):45-62. doi: 10.1006/fgbi.2000.1203.
The organization and roles of F-actin and microtubules in the maintenance and initiation of hyphal tip growth have been analyzed in Saprolegnia ferax and Neurospora crassa. In hyphae of both species, the apex is depleted of microtubules relative to subapical regions and near-normal morphogenesis occurs in concentrations of nocodazole or MBC which remove microtubules, slow growth, and disrupt nuclear positioning. In contrast, each species contains characteristic tip-high arrays of plasma membrane-adjacent F-actin, whose organization is largely unaltered by the loss of microtubules but disruption of which by latrunculin B disrupts tip morphology. Hyphal initiation and subsequent normal morphogenesis from protoplasts of both species and spores of S. ferax are independent of microtubules, but at least in S. ferax obligatorily involve the formation of F-actin caps adjacent to the hyphal tip plasma membrane. These observations indicate an obligatory role for F-actin in hyphal polarization and tip morphogenesis and only an indirect role for microtubules.
在水霉和粗糙脉孢菌中，已经对丝状肌动蛋白（F-肌动蛋白）和微管在菌丝顶端生长的维持和起始中的组织及作用进行了分析。在这两个物种的菌丝中，相对于亚顶端区域，顶端微管缺失，并且在诺考达唑或甲基苯骈三氮唑（MBC）浓度下会出现接近正常的形态发生，这两种物质会去除微管、减缓生长并扰乱核定位。相反，每个物种都含有与质膜相邻的具有特征性顶端高浓度的F-肌动蛋白阵列，其组织在很大程度上不会因微管缺失而改变，但用拉春库林B破坏F-肌动蛋白会扰乱顶端形态。这两个物种的原生质体以及水霉的孢子的菌丝起始和随后的正常形态发生都与微管无关，但至少在水霉中必然涉及到在菌丝顶端质膜附近形成F-肌动蛋白帽。这些观察结果表明F-肌动蛋白在菌丝极化和顶端形态发生中起必要作用，而微管仅起间接作用。
