Blakeslea trispora is known for its potential to produce an excess of carotenoids in mixed cultures of strains of opposite sex. The biosynthesis of β-carotene in B. trispora is activated not only by sex hormone trisporic acid but also by light, especially blue light. In fungi, the most intensively investigated blue-light reception proteins are WC-1 and WC-2, and the two proteins form a transcription factor complex which is called WCC by their PAS domains. Notably, multiple genes similar to wc-1 and wc-2 have been identified and characterized in Phycomyces, Mucor, and Rhizopus. Here we report that there are four members of wc-2-like gene family in B. trispora genome: Btwc-2a, Btwc-2b, Btwc-2c, and Btwc-2d. When the mycelia were exposed to blue light, their transcription levels are regulated differentially. Except for BtWC-2b, which only has a PAS domain, the other three proteins contain both a PAS domain and a ZnF domain. BtWC-2a interacts with either BtWC-1a or BtWC-1c to form different photoreceptor complexes in yeast two-hybrid assays, which is the unique situation not yet described in other fungi. In addition, the protein–protein docking analysis by the predicted 3D structures showed that the two complexes are structurally different. These results suggested that WC proteins of B. trispora are still involved in light regulation by forming WCC and the regulation mechanism of the photobiology appears to be more complex.

Blakeslea trispora以其在异性菌株的混合培养物中产生过量类胡萝卜素的潜力而闻名。B. trispora中β-胡萝卜素的生物合成不仅被性激素三孢酸激活，还被光，尤其是蓝光激活。在真菌中，研究最深入的蓝光接收蛋白是 WC-1 和 WC-2，这两种蛋白质形成转录因子复合物，其 PAS 结构域称为 WCC。值得注意的是，已经在Phycomyces、Mucor和Rhizopus 中鉴定并表征了与wc-1和wc-2相似的多个基因。这里我们报告一下wc-2有四名成员-B. trispora基因组中的类似基因家族：Btwc-2a、Btwc-2b、Btwc-2c和Btwc-2d。当菌丝体暴露在蓝光下时，它们的转录水平受到不同的调节。除了 BtWC-2b 只有一个 PAS 结构域外，其他 3 种蛋白质都包含一个 PAS 结构域和一个 ZnF 结构域。BtWC-2a 与 BtWC-1a 或 BtWC-1c 相互作用，在酵母双杂交试验中形成不同的光感受器复合物，这是其他真菌中尚未描述的独特情况。此外，通过预测的 3D 结构进行的蛋白质-蛋白质对接分析表明，这两种复合物在结构上是不同的。这些结果表明B. trispora 的WC 蛋白 仍然通过形成 WCC 参与光调节，光生物学的调节机制似乎更加复杂。