The Hoxb1 gene is transcribed to yield mRNA (Marshall et al. 1994, Studer et al. 1994, Ogura and Evans 1995, Chiba et al. 1997, Di Rocco et al. 1997, Langston et al. 1997, Wendling et al. 2001, Huang et al. 2002, Roelen et al. 2002).
Hoxb1 is expressed in mesoderm and neurectoderm of primitive streak stage embryos and then becomes restricted to rhombomeres of the hindbrain (Murphy et al. 1989, Wilkinson et al. 1989, Bogue et al. 1996). 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 (Murphy et al. 1989, Arenkiel et al. 2003).