Williams J G, Ceccarelli A, McRobbie S, Mahbubani H, Kay R R, Early A, Berks M, Jermyn K A
Cell. 1987 Apr 24;49(2):185-92. doi: 10.1016/0092-8674(87)90559-9.
We have isolated a gene that is very rapidly induced at the transcriptional level by DIF--a low molecular weight, diffusible factor necessary for stalk cell differentiation in Dictyostelium cells developing in vitro. The gene encodes a protein containing an N-terminal signal peptide preceding approximately 70 tandem repeats of a highly conserved 24 amino acid sequence with a high cysteine content. These features suggest it is an extracellular structural protein. During normal development, the gene is maximally expressed in the slug, in which the mRNA is very highly enriched in prestalk over prespore cells. The gene is not detectably expressed until the tipped aggregate stage, several hours later than prespore genes, suggesting that prespore cell differentiation precedes prestalk cell differentiation. The demonstration that DIF induces a gene normally only expressed in the prestalk zone of the slug provides strong evidence that DIF is a Dictyostelium morphogen.
我们分离出了一个基因，该基因在转录水平上会被DIF迅速诱导，DIF是一种低分子量的可扩散因子，对于体外发育的盘基网柄菌细胞中柄细胞的分化是必需的。该基因编码一种蛋白质，该蛋白质含有一个N端信号肽，其前面有约70个高度保守的24个氨基酸序列的串联重复，且半胱氨酸含量很高。这些特征表明它是一种细胞外结构蛋白。在正常发育过程中，该基因在蛞蝓体中表达量最高，其中mRNA在前柄细胞中比在孢子前体细胞中高度富集。直到顶端聚集期该基因才被检测到表达，这比孢子前体基因晚几个小时，表明孢子前体细胞分化先于前柄细胞分化。DIF诱导一个通常只在蛞蝓体前柄区表达的基因，这一证明为DIF是盘基网柄菌形态发生素提供了有力证据。
