Fig 2: Quantification of sterile alpha motif and histidine aspartic domain-containing protein 1 (SAMHD1) mRNA by quantitative PCR shows a dose-dependent increase in response to increasing concentrations of IFNγ. Differences from the baseline were significant (p < 0.05) for all concentrations of IFNγ at 6 and 12 h, and for all concentrations of IFNγ except 0.1 ng/mL at 18 h. After 24 h, SAMHD1 mRNA was significantly higher than control only in cells treated with 1.2 ng/mL of IFNγ.

Fig 3: Flow cytometric detection of cellular localization of total and phosphorylated SAMHD1 in purified primary feline CD4+ lymphocytes maintained in IL-2. Samples consisted of lymphocytes stained with a fluorochrome-labeled non-binding CXCR4 antibody as the negative control, and whole cells (A,B) or nuclei (C,D) were stained with anti-SAMHD1 or anti-pSAMHD 6 h after treatment with IFNγ. No significant differences in relative fluorescence attributable to IFNγ treatment were observed. Summary of results over time in whole cells (E) and nuclei (F).

Fig 4: Detection of SAMHD1 relative to lymphocyte antigens on primary feline PBMC. Representative plots show staining for SAMHD1, CD4, CD8, and CD21. A proportion of both T and B lymphocytes are positive for SAMHD1.

Fig 5: Detection of SAMHD1 by Western blotting in nuclear (A) and cytoplasmic (B) extracts of FeTJ cells treated with different concentrations of IFNγ for 6 h. Samples were collected pre-treatment and at 6 h post-treatment. HDAC1 and α-tubulin antibodies were used as nuclear and cytoplasmic protein loading controls, respectively.