ANALYSIS OF THE HOXD-3 GENE - STRUCTURE AND LOCALIZATION OF ITS SENSEAND NATURAL ANTISENSE TRANSCRIPTS

This study set out to investigate the structure and localized expressi on of the mouse homeobox-containing gene Hoxd-3., In addition to ident ifying a transcript of the type known from other Antennapedia (Antp)-l ike mammalian homeobox cDNAs, an antisense transcript was also detecte d, The antisense form of Hoxd-3 overlaps with 603 bp of the sense tran script including the homeobox, Active antisense transcription has been confirmed by RNA blot analysis with single-stranded probes and by the direction of splicing of an intron in the antisense transcript. The l ocalized expression of sense and antisense transcripts was compared by in situ hybridization, Hoxd-3 expression was observed from 8.5 days p .c., in the neural tube with a sharp border in the hind brain at the l evel of rhombomeres 4-5. In contrast, the earliest antisense expressio n was detected at 10.5 days p.c. in cDNA libraries. At 12.5 days p.c., sense and antisense transcripts colocalized in the liver. The possibl e role of antisense homeobox transcripts during liver and the hematopo ietic development is discussed.