| Autor: |
Zhao M; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China., Wang W; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China., Jin X; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China.; College of Fisheries and Life Science, Shanghai Ocean University, 999 Huchenghuan Road, Shanghai 201306, China., Liu Z; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China., Luo M; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China.; College of Fisheries and Life Science, Shanghai Ocean University, 999 Huchenghuan Road, Shanghai 201306, China., Fu Y; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China.; College of Fisheries and Life Science, Shanghai Ocean University, 999 Huchenghuan Road, Shanghai 201306, China., Zhan T; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China.; College of Fisheries and Life Science, Shanghai Ocean University, 999 Huchenghuan Road, Shanghai 201306, China., Ma K; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China., Zhang F; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China., Ma L; Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai 200090, China. |
| Abstrakt: |
The conserved role of juvenile hormone (JH) signals in preventing larvae from precocious metamorphosis has been confirmed in insects. Crustaceans have different metamorphosis types from insects; we previously proved that methyl farnesoate (MF) can prohibit larvae metamorphosis in mud crabs, but the molecular signal of this process still needs to be elucidated. In this study, methoprene-tolerant ( Met ) of Scylla paramamosain was obtained and characterized, which we named Sp-Met . Sp-Met contains a 3360 bp ORF that encodes 1119 amino acids; the predicted protein sequences of Sp-Met include one bHLH, two PAS domains, one PAC domain, and several long unusual Gln repeats at the C-terminal. AlphaFold2 was used to predict the 3D structure of Sp-Met and the JH binding domain of Met. Furthermore, the binding properties between Sp-Met and MF were analyzed using CD-DOCK2, revealing a putative high affinity between the receptor and ligand. In silico site-directed mutagenesis suggested that insect Mets may have evolved to exhibit a higher affinity for both MF or JH III compared to the Mets of crustaceans. In addition, we found that the expression of Sp-Met was significantly higher in female reproductive tissues than in males but lower in most of the other examined tissues. During larval development, the expression variation in Sp-Met and Sp-Kr-h1 was consistent with the immersion effect of MF. The most interesting finding is that knockdown of Sp-Met blocked the inhibitory effect of MF on metamorphosis in the fifth zoea stage and induced pre-metamorphosis phenotypes in the fourth zoea stage. The knockdown of Sp-Met significantly reduced the expression of Sp-Kr-h1 and two ecdysone signaling genes, Sp-EcR and Sp-E93 . However, only the reduction in Sp-Kr-h1 could be rescued by MF treatment. In summary, this study provides the first evidence that MF inhibits crustacean larval metamorphosis through Met and that the MF-Met→ Kr-h1 signal pathway is conserved in mud crabs. Additionally, the crosstalk between MF and ecdysteroid signaling may have evolved differently in mud crabs compared to insects. |
