In mouse embryos (PIASxbeta) PIAS2 activates expression of Hoxb1 (Garcia-Dominguez et al. 2006).
After activation by retinoic acid, the HOXB1 gene is transcribed to yield mRNA (in embryos in Giampaolo et al. 1989, in human embryonal carcinoma cells in Simeone et al. 1990, Ogura and Evans 1995).
In mouse embryos, Hoxb1 is expressed in mesoderm and neurectoderm of primitive streak stage embryos and then becomes restricted to rhombomeres of the hindbrain. Before rhombomere formation Hoxb1 is initially expressed in the region that becomes r3-7. After rhombomere formation Hoxb1 becomes restricted to r4 and is also observed in caudal mesoderm.
In mouse embryos PIASxbeta (PIAS2) activates Hoxb1 expression and Egr2 (Krox20) interferes with this activation (Garcia-Dominguez et al. 2006).
In mouse embryonal carcinoma cells and embryos Hoxb3 binds the Hoxb1 gene and negatively regulates transcription (Wong et al. 2011).