The methylotrophic yeast, Ogataea thermomethanolica TBRC656, is an attractive host organism for heterologous protein production owing to the availability of protein expression vectors and a genome-editing tool. In this study, we focused on mating-type switching and gene expression in order to elucidate its sexual life cycle and establish genetic approaches applicable for the strain. A putative mating-type gene cluster was identified in TBRC656 that is syntenic to the cluster in Ogataea parapolymorpha DL-1 (previously named Hansenula polymorpha). Like DL-1, TBRC656 possesses two mating loci, namely MATa and MATα, and also shows flip-flop mating-type switching. Interestingly, unlike any other methylotrophic yeast, TBRC656 robustly switched mating type during late growth in rich medium (YPD). Under nutrient depletion, mating-type switching was observed within one hour. Transcription from both MATa and MATα mating loci was detected during growth in YPD, and possibly induced upon nitrogen depletion. Gene expression from MATα was detected as a single co-transcript from a three-gene array (α2-α1-a1S). Deletion of a putative a1S ORF at the MATα locus had no observed effect on mating-type switching but demonstrated significant effect on mating-type gene expression at both MATa and MATα loci.

由于蛋白质表达载体和基因组编辑工具的可用性，甲基营养型酵母Ogataea thermomethanolica TBRC656是生产异源蛋白质的有吸引力的宿主生物。在这项研究中，我们专注于交配型转换和基因表达，以阐明其性生活周期并建立适用于该菌株的遗传方法。在TBRC656中鉴定出一个推定的交配型基因簇，该基因簇与Ogataea parapolymorpha DL-1（以前称为Hansenula polymorpha）中的簇同义。像DL-1一样，TBRC656具有两个交配基因座，即MAT a和MATα，并且还示出了触发器配合类型的开关。有趣的是，与任何其他甲基营养型酵母不同，TBRC656在富培养基（YPD）的后期生长过程中会稳固地切换交配类型。在营养耗尽的情况下，在一小时内观察到交配型转换。在YPD的生长过程中检测到MAT a和MATα交配位点的转录，并且可能在氮耗竭时被诱导。从基因表达MAT被检测为从三基因阵列中的单个共转录α（α 2- α 1 -一个1S）。在MAT上删除一个推定的1S ORFα位点对交配型转换没有观察到影响，但在MAT a和MATα基因座上均显示出对交配型基因表达的显着影响。