Fig. 3.

Model for direct regulation of sex-specific genes by STAT5b and HNF4α in male liver. In the model shown, GH pulse-activated STAT5 binds directly to and trans-activates its direct male-specific genes targets, which may include the family of male-specific Mup genes (Laz et al., 2009). HNF4α may also contribute to the expression of these genes. STAT5 and HNF4α may also directly bind to and repress female-specific genes, as shown. Some of the genes that serve as primary targets of STAT5 and HNF4α may also mediate the effects of these transcription factors on their downstream (i.e., indirect) targets, as shown in Fig. 4.