Molecular characterization and expression pattern analysis of Sirtuin family genes in the eastern honeybee, Apis cerana

Sirtuin proteins are a family of evolutionarily conserved NAD(+)-dependent deacetylase enzymes which play crucial roles in regulating insect metabolism, maintaining genome stability, and lifespan. However, there is no report on the genome-wide analysis of the Sirtuin gene family in the eastern honeybee, Apis cerana. Here, 6 Sirtuin genes (AcSirt1, AcSirt2, AcSirt4 similar to AcSirt7) were obtained in the A. cerana genome, which were located on 6 different chromosomes and were all single-copy genes. Gene structure analysis revealed that these 6 genes were all multi-exon genes. The Sirtuin family genes contained 9 conserved motifs and 5 conserved domains, which exhibited typical Sirtuin protein structural characteristics. The phylogenetic analysis of the Sirtuin family genes indicates that A. cerana lacked the Sirt3 gene, and the 6 Sirtuin encoding genes could be clustered into 5 groups and 6 branches, showing high homology with the Apis mellifera and the Apis dorsata. The results of the tissue and period expression profiles by qRT-PCR indicated that the 6 Sirtuin family genes showed transcriptional activity in different tissues of worker bees, and the gene expression level reached the peak in the 4-day-old larvae and pupa stages. It was speculated that Sirtuin genes expression level was affected by fasting behavior, caloric restriction and organ differentiation during different developmental stages of A. cerana. Meanwhile, the differential expression patterns of Sirtuin genes in various tissues further demonstrated the diversity and complexity of their functions, providing a basis for target selection in future studies on the functionality of Sirtuin genes.