“The secreted novel AID/APOBEC-like deaminase 1 (SNAD1) could play an important role in fish immunology (7355)”

The secreted novel AID/APOBEC-like deaminase 1 (SNAD1) could play an important role in fish immunology

Introduction: AID/APOBECs are a group of zinc-dependent cytidine deaminases that catalyse the deamination of bases in nucleic acids, resulting in a transition from cytidine to uridine. Secreted novel AID/APOBEC-like deaminases (SNADs) are unique among all intracellular classical AID/APOBECs due to their characteristic signal peptide. SNADs are central to antibody diversity and antiviral defence. Currently, no information is available on SNADs, including their protein characterisation, biochemical properties and catalytic activity.

Methodology: We used several in silico and in vivo approaches to better define the biological function of SNAD1. We analysed the phylogeny of SNADs, their common structural features and potential structural variations in fish species. Additionally, we searched published fish data and identified previously ‘uncharacterised proteins’ and transcripts as SNAD1 sequences. To validate the in silico predictions, we performed RT-qPCR-based expression studies of several SNAD1 gene variants in carp during temperature adaptation, as well as during infections with Aeromonas salmonicida, carp edema virus, and koi herpes virus.

Results: Our analysis provides strong evidence of the universal presence of multiple SNAD1 proteins/transcripts in fish, which are expressed after hatching and predominantly in anatomical organs associated with the immune system. A review of immunological research suggests that SNAD1 plays a role in the immune response to infection or immunization, as well as in interactions with the gut microbiota. We also found that SNAD1 is associated with temperature acclimation, environmental pollution and sex-based expression differences, with females exhibiting higher levels. During experimental infections, we observed that SNAD1 gene variants in carp exhibited different response patterns to temperature adaptation and bacterial and viral infections.

Conclusions: This dual sensitivity to environmental and pathogenic stressors highlights the importance of SNAD1 for fish, as it may improve thermotolerance and immune defence. Elucidating the biological role of SNADs is an exciting new area of research relating to the function of DNA and/or RNA editing in fish biology.

1. ADAMEK, MIKOLAJ, UNIVERSITY OF VETERINARY MEDICINE HANNOVER, Presenter
2. Majewska, Anna, Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Author
3. Dietrich, Mariola, Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Author
4. Budzko, Lucyna, Department of Molecular and Systems Biology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland, Author
5. Figlerowicz, Marek, Department of Molecular and Systems Biology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland, Author
6. Ciereszko, Andrzej, Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Author