A novel homeobox nkch4 gene from the Drosophila 93E region

We have cloned a Drosophilia melanogaster homeobox gene that maps to bands 93D9-E2 on the right arm of the third chromosome, in the proximal region of the NK-homeobox gene cluster. Like NK-1 and nine other known homeobox genes, nkch4 (NK-cluster homeobox 4) contains an intron between the homeodomain codons for Glu44 and Val45. The nkch4 homeodomain sequence is most related to that of the human HOX11 (tcl3) T-cell oncogene (57% homology), but differs from all other homeobox genes at several conserved residues in the third helix of the homeodomain, known to be important for DNA recognition. Low levels of nkch4 transcripts were detected during late stages of embryogenesis as well as in third instar larvae and pupae. In late embryos nkch4 is expressed in the developing CNS.