As inferred from the Hoxd1 homolog in mouse embryos, HOXD1 is not expressed in hindbrain. In mouse, expression of Hoxd1 begins at E8.5 in caudal lateral mesoderm. At E9.5 to E11.5 Hoxd1 expression is observed in prosomeres p2 and p3 of the diencephalon, dermatomes, urogenital tubercle, and tail bud. Expression is inducible by retinoic acid in neuroblastoma cells, however it is unknown if the induction is direct or indirect (Manohar et al. 1996, Zha et al. 2012). Nerve Growth Factor induces Hoxd1 expression in nociceptors of mouse embryos. As inferred from human posterior HOXD genes in primary human fibroblasts (Lan et al. 2007), other anterior HOX genes, and mouse Hoxd1, the activation of HOXD1 chromatin may be associated with loss of methylation at lysine-27 of histone H3 (H3K27me3) loss of polycomb repressive complex 2 (PRC2), gain of histone acetylation, and gain of methylation at histone H3K4. Like other Hox gene clusters, the HoxD cluster in mouse changes position relative to other loci in the nucleus during activation.