Currently, the data on presence of adenoviral receptors in fish are very limited. We have used a ready-to-image mouse recombinant adenoviral vectors with the GCaMP6m calcium sensor, which are usually applied for the dorsal CA1 hippocampus of mice, but have not previously been used for the gene delivery in the fishes brain. The work objective was to assess the ability of the recombinant adenovirus (rAAV) labeling in the brain cells of juvenile chum salmon and the subsequent determination of the phenotype of rAAV-labeled cells with the help of confocal microscopy. The gene delivery in vivo was performed, using the injection of a ready-to-image FITS-associated viral vector directly into the mesencephalic tegmentum of the one-year-old juvenile Oncorhynchus keta. An assessment of the viral delivery level was made 1 week after the vector injection. Using fluorescent microscopy and confocal scanning microscopy, the expression of adenoviral vector in the tegmentum cells of a juvenile O. keta was evaluated, followed by IHC analysis of the neuron-specific HuCD protein in combination with DAPI staining. The results of immunofluorescence analysis have shown a colocalization of cells expressing the adenoviral vector with green fluorescence, and with a neuron-specific HuCD protein – with red fluorescence. The results obtained indicate that tegmentum cells of juvenile O. keta expressing an adenoviral vector are corresponding to a neuron-specific line of the O. keta brain cells, what witnesses the ability of a mammalian hippocampal adenoviruses to incorporate into the fishes CNS neurons. Thus, hippocampus-specific mammalian adenoviral vectors can integrate into fish brain neurons, followed by expression of viral proteins, and that the tegmentum neurons of a juvenile chum salmon contain a mammalian adenovirus receptor homolog.
Пущина Е. В.