Chandrasekhar A, Ennis H L, Soll D R
Department of Biology, University of Iowa, Iowa City 52242.
Development. 1992 Oct;116(2):417-25. doi: 10.1242/dev.116.2.417.
When developing cultures of Dictyostelium discoideum are disaggregated at any time prior to cell wall formation and challenged to reinitiate development, amoebae will progress through the original sequence of morphogenetic stages, but the second time through they will do so in roughly one-tenth the original time, a process known as 'rapid recapitulation'. However, if disaggregated cells are suspended in nutrient medium, they enter a program of dedifferentiation during which they lose the capacity to rapidly recapitulate after an 80 minute lag period in a process known as 'erasure'. Here we show that cells that have completed the morphogenetic program and emerge from spore coats in the process of germination have also erased. In addition, the germination-specific 270 gene family is expressed during induced dedifferentiation in a unique fashion, and a germination-defective mutant exhibits a dramatic delay in erasure without concomitant defects in the program of gene regulation accompanying induced dedifferentiation. These results suggest for the first time that induced dedifferentiation and spore germination share some common processes in converting cells from a developmental to vegetative state.
当发育中的盘基网柄菌在细胞壁形成之前的任何时间被分散，并被刺激重新开始发育时，变形虫将经历形态发生阶段的原始序列，但第二次经历时，它们将在大约原来十分之一的时间内完成，这个过程被称为“快速重演”。然而，如果分散的细胞悬浮在营养培养基中，它们会进入一个去分化程序，在此期间，它们在80分钟的延迟期后失去快速重演的能力，这个过程被称为“消除”。在这里我们表明，已经完成形态发生程序并在萌发过程中从孢子壁中出现的细胞也经历了消除。此外，萌发特异性的270基因家族在诱导去分化过程中以独特的方式表达，并且一个萌发缺陷突变体在消除过程中表现出显著延迟，而在伴随诱导去分化的基因调控程序中没有相应的缺陷。这些结果首次表明，诱导去分化和孢子萌发在将细胞从发育状态转变为营养状态的过程中共享一些共同过程。
