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Research Project: Adding Value to Plant-Based Waste Materials through Development of Novel, Healthy Ingredients and Functional Foods

Location: Healthy Processed Foods Research

Title: Overexpression of ribonucleotide reductase small subunit, RNRM, increases cordycepin biosynthesis in transformed cordyceps militaris

item ZHANG, HAN - Chengdu University
item WANG, YU-XIAN - Chengdu University
item TONG, XIN-XIN - Chengdu University
item Yokoyama, Wallace - Wally
item CAO, JING - Chengdu University
item WANG, FANG - Chengdu University
item PENG, CHENG - Chengdu University
item GUO, JIN-LIN - Chengdu University

Submitted to: Journal of Natural Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2019
Publication Date: 5/20/2020
Citation: Zhang, H., Wang, Y., Tong, X., Yokoyama, W.H., Cao, J., Wang, F., Peng, C., Guo, J. 2020. Overexpression of ribonucleotide reductase small subunit, RNRM, increases cordycepin biosynthesis in transformed cordyceps militaris. Journal of Natural Medicine. 18(5):393-400.

Interpretive Summary: The biosynthesis of cordycepin, an anticancer and antiviral agent found in the mushroom Cordyceps militaris, was investigated. An important step is believed to be the ribonucleotide reductase. A reductase was overexpressed in C. militaris and increased the amount of cordycepin suggesting its importance in the biosynthetic pathway.

Technical Abstract: Cordycepin was the first adenosine analogue used as an anticancer and antiviral agent, which is extracted from Cordyceps militaris and hasn’t been biosynthesized until now. This study was first conducted to verify the role of ribonucleotide reductases (RNRs, the two RNR subunits, RNRL and RNRM) in the biosynthesis of cordycepin by over expressing RNRs genes in transformed C. militaris. Quantitative real-time PCR (qRT-PCR) and western blotting results showed that the mRNA and protein levels of RNR subunit genes were significantly upregulated in transformant C. militaris strains compared to the control strain. The results of the HPLC assay indicated that the cordycepin content was significantly higher in the C. militaris transformants carrying RNRM than in the wild-type strain, whereas in the C. militaris transformant carrying RNRML, the content of cordycepin was preferentially downregulated. For the C. militaris transformant carrying RNRL, the content of cordycepin wasn’t remarkably changed. Furthermore, we revealed that inhibiting RNRs with Triapine (3-AP) almost abrogated the upregulation of cordycepin. Therefore, our results suggested that RNRM can probably directly participate in cordycepin biosynthesis by hydrolyzing adenosine, which is useful for improving cordycepin synthesis and helps to satisfy the commercial demand of cordycepin in the field of medicine.