- Inhibition of retinoic acid-induced activation of 3' human HOXB genes by antisense oligonucleotides affects sequential activation of genes located upstream in the four HOX clusters. Faiella, A., Zappavigna, V., Mavilio, F., Boncinelli, E. Proc. Natl. Acad. Sci. U.S.A. (1994)