Abstract:

This study aimed to investigate the function of the RNA transcription factor Capicua （AmCIC） in the Apis mellifera. Bioinformatic analyses were conducted to predict the physicochemical properties， molecular characteristics， conserved motifs， and functional domains of AmCIC， and its relative expression levels were examined by RT-qPCR. The results showed that the predicted molecular formula of AmCIC is C₉₀₅₀H₁₄₃₃₉N₂₆₅₃O₂₉₃₂S₅₉， with a molecular weight of 209.11 kD， an aliphatic index of 62.64， and an isoelectric point of 7.42. The protein exhibits a hydrophilicity index of -0.760 and lacks both transmembrane domains and signal peptides. Subcellular localization analysis indicated that AmCIC is distributed in the nucleus， mitochondria， and cytoplasm， suggesting that it is a hydrophilic， non-transmembrane intracellular protein. Comparative analysis revealed that CIC proteins from seven bee species share two conserved domains and five conserved motifs， with A. mellifera and Apis laboriosa clustering closely in phylogenetic analyses. Expression profiling showed that AmCIC is expressed in all examined tissues of adult worker bees， with the highest expression detected in the brain. During larval development， AmCIC expression was highest at the egg stage， while among adult workers of different ages， peak expression occurred at 12 days post-emergence. Notably， following Ascosphaera apis inoculation， AmCIC expression in the larval midgut was extremely significantly downregulated （P<0.001）， indicating that AmCIC is involved in the host response to pathogen infection. Collectively， these results suggest a potential role for this transcription factor in honeybee development and antifungal immune responses.

Key words: Apis mellifera, Capicua transcription factor, molecular characteristics, expression patterns, Ascosphaera apis