AccERK2, A MAP KINASE GENE FROM Apis cerana cerana, PLAYS ROLES IN STRESS RESPONSES, DEVELOPMENTAL PROCESSES, AND THE NERVOUS SYSTEM

Extracellular signal-regulated kinase (ERK), a mitogen-activated protein kinase (MAPK), plays roles in a variety of cellular responses. However, limited information is available on the relationship between ERKs and environmental stresses. In this report, an ERK gene, AccERK2, was cloned and characterized from Apis cerana cerana. Polypeptide sequence alignment revealed that the single-copied AccERK2 shares high identity with other known ERKs and contains the typical conserved ThrGluTyr (TEY) motif in its activation loop. Genomic sequence analysis revealed that the seven exons of AccERK2 are interrupted by six introns, and the seventh intron is located in the 3' untranslated region. Semi-quantitative reverse transcription (RT-PCR) indicated that AccERK2 was expressed at higher levels in the larval and pupal stages than in the adult stage. AccERK2 was also most highly expressed in the brain. The expression of AccERK2 was induced by abiotic stresses, including heat, ion irradiation, oxidative stress, and heavy metal ions. Based on these results, it appears that AccERK2 in A. cerana cerana participates in developmental processes, the nervous system, and responses to environmental stressors.