Gamma radiation triggers synthesis of tropomyosin and actin in salivary gland cells of Chironomus ramosus

Chironomus ramosus, an Indian tropical midge, exhibits remarkable tolerance to radiation and desiccation stress, making it an ideal model for studying cellular adaptive responses. The salivary gland (SG) cells of fourth instar larvae, known for their high metabolic activity, serve as a valuable system for investigating molecular mechanisms underlying stress response. This study aimed to investigate the significance of tropomyosin and actin in cellular recovery post gamma radiation exposure from salivary gland cells of Chironomus ramosus larvae in mediating the radiation-induced stress response. The SG cells were isolated from control and gamma-irradiated fourth instar larvae and subjected to metabolic labeling ([35S] methionine) to assess protein synthesis dynamics. Western blotting and immunofluorescence staining confirmed the radiation-induced expression of tropomyosin and actin following 2200 Gy gamma radiation exposure. Semi-quantitative RT-PCR was employed to confirm transcriptional upregulation of the target genes. Gamma radiation exposure triggered two to three-fold elevation in tropomyosin and actin protein levels in SG cells of Chironomus ramosus, with sustained upregulated expression through 24–48 h of post-irradiation recovery. The corresponding mRNA expression profiles paralleled these protein-level changes, reinforcing the notion of radiation-induced transcriptional regulation of cytoskeletal proteins in SG cells of C. ramosus. This study provides compelling evidence that tropomyosin and actin stress fibers are overexpressed in C. ramosus larvae following gamma radiation exposure, suggesting a crucial role for cytoskeletal remodeling in radiation-induced adaptive responses.