Narita Takaaki B, Chen Zhi-hui, Schaap Pauline, Saito Tamao
Graduate School of Science and Technology, Sophia University, Tokyo, Japan; Research Fellow of Japan Society for the Promotion of Science (DC2), Tokyo, Japan.
College of Life Sciences, University of Dundee, Dundee, United Kingdom.
PLoS One. 2014 Sep 15;9(9):e106634. doi: 10.1371/journal.pone.0106634. eCollection 2014.
In our previous study we found that the expression of stlA showed peaks both in the early and last stages of development and that a product of SteelyA, 4-methyl-5-pentylbenzene-1,3-diol (MPBD), controlled Dictyostelium spore maturation during the latter. In this study we focused on the role of SteelyA in early stage development.
Our stlA null mutant showed aggregation delay and abnormally small aggregation territories. Chemotaxis analysis revealed defective cAMP chemotaxis in the stlA null mutant. cAMP chemotaxis was restored by MPBD addition during early stage development. Assay for cAMP relay response revealed that the stlA null mutant had lower cAMP accumulation during aggregation, suggesting lower ACA activity than the wild type strain. Exogenous cAMP pulses rescued the aggregation defect of the stlA null strain in the absence of MPBD. Expression analysis of cAMP signalling genes revealed lower expression levels in the stlA null mutant during aggregation.
Our data indicate a regulatory function by SteelyA on cAMP signalling during aggregation and show that SteelyA is indispensable for full activation of ACA.
在我们之前的研究中，我们发现stlA的表达在发育的早期和后期均出现峰值，并且SteelyA的一种产物4-甲基-5-戊基苯-1,3-二醇（MPBD）在后期控制盘基网柄菌的孢子成熟。在本研究中，我们聚焦于SteelyA在早期发育中的作用。
我们的stlA基因敲除突变体表现出聚集延迟和异常小的聚集区域。趋化性分析显示stlA基因敲除突变体的cAMP趋化性存在缺陷。在早期发育过程中添加MPBD可恢复cAMP趋化性。cAMP中继反应检测显示，stlA基因敲除突变体在聚集过程中cAMP积累较低，表明其ACA活性低于野生型菌株。在没有MPBD的情况下，外源性cAMP脉冲挽救了stlA基因敲除菌株的聚集缺陷。cAMP信号基因的表达分析显示，在聚集过程中，stlA基因敲除突变体中的表达水平较低。
我们的数据表明SteelyA在聚集过程中对cAMP信号具有调节功能，并表明SteelyA对于ACA的完全激活是不可或缺的。
