Weijer C J, Durston A J
J Embryol Exp Morphol. 1985 Apr;86:19-37.
We describe the effect of cyclic AMP on regulation of the proportion of prespore and prestalk cells in Dictyostelium discoideum. Prespore and prestalk cells from slugs were enriched on Percoll density gradients and allowed to regulate in suspension culture under 100% oxygen. The transition of prespore to prestalk cells is blocked by cAMP, while cAMP phosphodiesterase and caffeine cause a decrease in the number of prespore cells. This suggests that extracellular cAMP plays a role in cell type proportioning by inhibiting the conversion of prespore to prestalk cells. Low concentrations of cAMP prevent the conversion of prestalk to prespore cells; the same effect is seen with hydrolysis products of cAMP, 5 AMP, adenosine and also adenine. We suggest that, when low concentrations of cAMP are added to regulating cells, the cAMP itself is quickly broken down and the breakdown products thereafter inhibit the prestalk-to-prespore conversion. The relevance of these findings is discussed in the context of an non-positional double-negative feedback model for cell type homeostasis.
我们描述了环磷酸腺苷（cAMP）对盘基网柄菌中前孢子细胞和前柄细胞比例调节的影响。从蛞蝓中分离得到的前孢子细胞和前柄细胞在Percoll密度梯度上进行富集，并在100%氧气条件下于悬浮培养中进行调节。cAMP可阻断前孢子细胞向前柄细胞的转变，而cAMP磷酸二酯酶和咖啡因会导致前孢子细胞数量减少。这表明细胞外cAMP通过抑制前孢子细胞向前柄细胞的转化，在细胞类型比例调节中发挥作用。低浓度的cAMP可阻止前柄细胞向前孢子细胞的转化；cAMP的水解产物5'-AMP、腺苷以及腺嘌呤也有同样的效果。我们认为，当向调节细胞中添加低浓度的cAMP时，cAMP本身会迅速分解，其分解产物随后会抑制前柄细胞向前孢子细胞的转化。我们将在细胞类型稳态的非位置双负反馈模型的背景下讨论这些发现的相关性。
