Interleukin-7 (IL7) up-regulates Cytokine-inducible SH2-containing protein (CISH), Suppressor of cytokine signaling 1(SOCS1), Suppressor of cytokine signaling 2(SOCS2) and Suppressor of cytokine signaling 3 (SOCS3) mRNA transcripts in primary human CD8 T cells. IL7 induces CISH and SOCS1-3 transcripts via the JAK/STAT5 signaling pathway (Ghazawi et al. 2016).
Signal transducer and activator of transcription 5A (STAT5A) and Signal transducer and activator of transcription 5B (STAT5B) dimers bind to similar core gamma-interferon activated sequence (GAS) motifs (Soldaini et al., 2000). STAT5 also form homo- and hetero-tetramers with distinct or expanded DNA-binding properties. This is a black box event because apart of the mentioned here genes could be another subset of genes up or downregulated by STAT5. Genes that are regulated by STAT5 include Interleukin-2 receptor alpha (IL2RA) (John et al. 1996), TNFSF11 (RANKL), Connexin-26 (GJB2) and Cyclin D1 (Hennighausen & Robinson, 2005). A comprehensive listing of hepatic STAT5B regulated genes is available from microarray/STAT5B knockout mice (Clodfelter et al. 2006), and similarly for STAT5-dependent genes regulated by the GH receptor (Rowland et al. 2005, Barclay et al. 2011).