Palonen Elina K, Raina Sheetal, Brandt Annika, Meriluoto Jussi, Keshavarz Tajalli, Soini Juhani T
Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Åbo, Finland.
Department of Life Sciences, University of Westminster, London W1W 6UW, UK.
Microorganisms. 2017 Mar 14;5(1):12. doi: 10.3390/microorganisms5010012.
Filamentous fungi of the Ascomycota phylum are known to contain a family of conserved conidiation regulating proteins with distinctive velvet domains. In Aspergilli, this velvet family includes four proteins, VeA, VelB, VelC and VosA, and is involved in conidiation and secondary metabolism along with a global regulator LaeA. In A. terreus, the overexpression of LaeA has been observed to increase the biogenesis of the pharmaceutically-important secondary metabolite, lovastatin, while the role of the velvet family has not been studied. The secondary metabolism and conidiation of A. terreus have also been observed to be increased by butyrolactone I in a quorum-sensing manner. An enlightenment of the interplay of these regulators will give potential advancement to the industrial use of this fungus, as well as in resolving the pathogenic features. In this study, the Aspergillus terreus MUCL 38669 transcriptome was strand-specifically sequenced to enable an in-depth gene expression analysis to further investigate the transcriptional role of butyrolactone I in these processes. The sequenced transcriptome revealed intriguing properties of the velvet family transcripts, including the regulator laeA, and uncovered the velC gene in A. terreus. The reliability refining microarray gene expression analysis disclosed a positive regulatory role for butyrolactone I in laeA expression, as well as an influence on the expression of the canonical conidiation-regulating genes under submerged culture. All of this supports the suggested regulative role of butyrolactone I in A. terreus secondary metabolism, as well as conidiation.
已知子囊菌门的丝状真菌含有一类具有独特天鹅绒结构域的保守的分生孢子形成调节蛋白家族。在曲霉菌中，这个天鹅绒家族包括四种蛋白，即VeA、VelB、VelC和VosA，它们与全局调节因子LaeA一起参与分生孢子形成和次级代谢。在土曲霉中，已观察到LaeA的过表达会增加具有重要药用价值的次级代谢产物洛伐他汀的生物合成，而天鹅绒家族的作用尚未得到研究。还观察到丁内酯I以群体感应的方式增加土曲霉的次级代谢和分生孢子形成。了解这些调节因子之间的相互作用将为这种真菌的工业应用以及解决其致病特性带来潜在进展。在本研究中，对土曲霉MUCL 38669转录组进行了链特异性测序，以便进行深入的基因表达分析，进一步研究丁内酯I在这些过程中的转录作用。测序的转录组揭示了天鹅绒家族转录本（包括调节因子laeA）的有趣特性，并发现了土曲霉中的velC基因。经过可靠性优化的微阵列基因表达分析揭示了丁内酯I对laeA表达具有正调节作用，以及对深层培养条件下典型的分生孢子形成调节基因的表达有影响。所有这些都支持丁内酯I在土曲霉次级代谢以及分生孢子形成中具有所提出的调节作用。
