Genome-wide identification and immunological expression analysis of the C3HC4-type zinc finger protein genes in the silkworm, Bombyx Mori

The ubiquitous C3HC4 nucleic acid-binding motif is widely distributed across diverse organisms. C3HC4-type RING finger genes constitute a large family and are essential for plant development as well as responses to biotic and abiotic stress. Zinc finger protein domains exhibit considerable variation, indicating that most proteins have unique binding sites and functions. However, the binding sites and functions of most C3HC4-ZF proteins are still largely unknown. In this study, 32 C3HC4 genes were identified in the silkworm (B. mori). Phylogenetic analysis showed that C3HC4-ZF protein genes in the silkworm can be grouped into four main clusters, with the 32 genes distributed across 18 chromosomes. Tissue-specific expression patterns were observed for some C3HC4-ZF protein genes in larval tissues of silkworms. Notably, several C3HC4-ZF genes were found to be expressed explicitly during silk gland development. Four genes—BMZFPC3HC43, BMZFPC3HC411, BMZFPC3HC413, and BMZFPC3HC417 were selected for real-time quantitative PCR analysis in the silk gland. The results showed distinct expression patterns among these genes. Additionally, given the high expression of C3HC4 zinc finger protein genes in the fat body, qRT-PCR was performed to investigate the expression profiles of six C3HC4-ZF genes in the fat body after exposure to pathogenic microorganisms. The results indicated significant differences in their expression patterns, suggesting a potential role in the immune response. These findings provide a foundation for further functional studies of C3HC4-ZF genes in Lepidoptera insects. Moreover, the results offer valuable insights into the molecular mechanisms underlying silk gland development and immunity in the silkworm.