A new homeo-box is present in overlapping cosmid clones which define the mouse Hox-1 locus.

Abstract
A new murine homeo‐box (Hox1‐3) has been isolated and studied with respect to its structure and transcriptional pattern. This homeo‐box is part of a gene which is specifically regulated during mouse prenatal development and expressed in a restricted number of teratocarcinoma tumours as well as in adult testis. Hox1‐3 is shown to be a member of a cluster of at least four homeo‐boxes lying within a 75‐kb segment of DNA on mouse chromosome 6. The structure of the whole cluster, the Hox‐1 locus is presented.