A novel MKK gene (AjMKK3/6) in the sea cucumber Apostichopus japonicus: Identification, characterization and its response to pathogenic challenge

• Published in: Fish & shellfish immunology 2017-02, Vol.61, p.24-33
• Main Authors: Wang, Yi, Chen, Ge, Li, Kaiquan, Sun, Jingxian, Song, Jian, Zhan, Yaoyao, Zhang, Xiangxiang, Yang, Limeng, Chang, Yaqing
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Apostichopus japonicus; Base Sequence; Cloning, Molecular; DNA, Complementary - genetics; DNA, Complementary - metabolism; Expression analysis; Immunity, Innate; Mitogen-activated protein kinase kinase 3/6; Mitogen-Activated Protein Kinase Kinases - chemistry; Mitogen-Activated Protein Kinase Kinases - genetics; Mitogen-Activated Protein Kinase Kinases - metabolism; Molecular Conformation; Phylogeny; Protein Structure, Secondary; Real-Time Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Messenger - metabolism; Sequence Alignment; Stichopus - genetics; Stichopus - immunology; Stichopus - microbiology; Vibrio - physiology; Vibrio splendidus infection
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2016.12.017

The mitogen-activated protein kinase kinases (MKKs) are key components of MAP kinase (MAPK) cascades and function as redox-regulated signaling factors in pathological and physiological processes. In this study, we identified a novel MKK3/6 gene in the sea cucumber Apostichopus japonicus (designated as AjMKK3/6) by transcriptome database mining and rapid amplification of cDNA ends (RACE) approaches. Sequence analysis and protein structure prediction showed that AjMKK3/6 is highly conserved as compared to those from other invertebrate and vertebrate species. Molecular phylogeny result revealed that AjMKK3/6 exhibited a closest relationship with that from Strongylocentrotus purpuratus. Quantitative real-time PCR was employed to determine the expression profiles of AjMKK3/6 in healthy adult A. japonicus tissues and in coelomocytes after Vibrio splendidus infection in vivo, respectively. As results shown, AjMKK3/6 was ubiquitously expressed in all examined tissues of healthy adult A. japonicus with a relative expression level from high to low as body wall > tube feet > coelomocytes > respiratory tree > intestine > longitudinal muscle. Significant expression changes of AjMKK3/6 in coelomocytes were observed at 12 h- and 72 h-after V. splendidus infection, respectively. In general, the current study will enrich our knowledge of characterizations and immno-functions of MKK3/6 in sea cucumbers. •AjMKK3/6in the sea cucumber Apostichopus japonicus was cloned and characterized.•AjMKK3/6 expressed ubiquitously in all examined tissues of adult A. japonicus.•The expression profiles of AjMKK3/6 in coelomocytes altered after pathogen challenge in vivo.