CRISPR-Cas9 Screening and Simulated Infection Transcriptomic Identify Key Drivers of Innate Immunity in Bactrian Camels.

The Bactrian camel (Camelus bactrianus), with its unique physiological adaptations and immune characteristics, represents a highly valuable model for innate immunity research. However, a systematic dissection of its innate immune gene repertoire and the key functional drivers within its immune response remains limited. This study integrated CRISPR-Cas9 knockout screening with time-resolved transcriptomic profiling to systematically unveil the immune regulatory mechanisms in camel dermal fibroblasts challenged with the viral mimic poly(I:C) and the bacterial mimic LPS. The CRISPR screen successfully identified 59 key genes conferring a survival advantage under lethal pathogenic challenge. The gene sets required for resisting viral versus bacterial mimics were entirely distinct, revealing divergent genetic underpinnings. Transcriptomic analysis further delineated a dynamic reprogramming of gene expression, uncovering a shared core immune response program alongside significant stimulus-specific regulation. Integrative analysis pinpointed pivotal genes, such as HSP90AA1 in the antiviral process and CSF1 in the antibacterial process, which played critical roles at both the functional screening and transcriptional regulatory levels. These key genes exhibited dynamic and evolving co-expression networks across different time points, indicating their temporally specific regulatory roles throughout the immune response. By combining functional genomics and transcriptomics, this study provides the first systematic mapping of the innate immune landscape and its dynamic regulation in the Bactrian camel, not only deepening the understanding of camelid immunobiology but also offering a new framework and insights for evolutionary studies of immune adaptation mechanisms in mammals.