Xie Y J, Kwong L, Weeks G
Department of Microbiology, University of British Columbia, Vancouver, Canada.
Dev Biol. 1991 May;145(1):195-200. doi: 10.1016/0012-1606(91)90225-r.
The differentiation inducing factor (DIF) is essential for stalk cell formation in monolayers of Dictyostelium discoideum and is necessary for the expression of several prestalk cell-specific genes. DIF activity has been fractionated into a major species, designated DIF-1, and several minor species, including DIF-2. Although DIF-1 is an excellent inducer of stalk cell formation from vegetative cells, it is a poor inducer of stalk cell formation from prestalk cells. In contrast, DIF-2 is more active for the conversion of prestalk cells into stalk cells, than for the conversion of vegetative cells to stalk cells. The same results were obtained regardless of whether chemically synthesized or naturally occurring components were utilized. In addition, stalk cell formation was three- to fourfold higher when vegetative cells were incubated with DIF-1 for a suboptimal period and then subsequently incubated with DIF-2, than when cells were incubated with DIF-2 first and then subsequently with DIF-1. These results indicate a distinct role for DIF-2 during stalk cell formation and suggest the possibility that DIF-1 and DIF-2 act sequentially.
分化诱导因子（DIF）对于盘基网柄菌单层中的柄细胞形成至关重要，并且对于几个前柄细胞特异性基因的表达是必需的。DIF活性已被分离成一种主要形式，命名为DIF-1，以及几种次要形式，包括DIF-2。尽管DIF-1是从营养细胞诱导柄细胞形成的优秀诱导剂，但它对于从前柄细胞诱导柄细胞形成效果不佳。相反，DIF-2在前柄细胞向柄细胞的转化中比在营养细胞向柄细胞的转化中更具活性。无论使用化学合成成分还是天然成分，都得到了相同的结果。此外，当营养细胞先用DIF-1进行次优时间的孵育，然后再用DIF-2孵育时，柄细胞的形成比先将细胞用DIF-2孵育然后再用DIF-1孵育时高3至4倍。这些结果表明DIF-2在柄细胞形成过程中具有独特作用，并提示DIF-1和DIF-2可能依次发挥作用。
