Specific expression of the Hox 1.3 homeo box gene in murine embryonic structures originating from or induced by the mesoderm.

Abstract

The murine Hox 1.3 homeo box‐containing gene is expressed largely in mesoderm‐derived or mesoderm‐induced embryonal structures, as evidenced by in situ hybridization techniques. Expression is spatially limited to the thoracic region, specifically to components of segmental origin such as embryonal ribs and vertebrae and their precursors such as the equivalent sclerotomes, somites and somatic condensations. In addition, expression can be found in parts of embryonal lung, stomach tissue, gut and kidney, tissues whose formation is based on induction of region‐specific mesoderm, as well as in some ectoderm‐derived tissues. The expression is temporally controlled for the transcripts and can only be detected while the thoracic structures are being formed (days 8‐13), but not at day 18 of gestation when the embryo is mature. These data suggest a role of Hox 1.3 gene in the generation of tissues derived from or induced by the embryonal mesoderm.

Identification of Transcriptional Targets of HOXA5

“…The data presented in this paper show that like human HOXA5, mouse Hoxa5 may directly control the expression of Ptn during development. Most strikingly, the expression of Hoxa5 coincides well with that of Ptn both in the time window and locations during development (24,(45)(46)(47). Because both of Hoxa5 and Ptn are expressed in the central nervous system, lung, and gut, it is possible that HOXA5 may directly dictate functions of PTN in the development of these tissues.…”

“…Hybridization was performed as described (19). Briefly, double-stranded cDNA was synthesized from 15 g of total RNA with SuperScript Choice System (Invitrogen) by using oligo(dT) 24 primers, with a T7 RNA polymerase promoter site added to its 3Ј-end (Genset Corp, La Jolla, CA). The isolated cDNA was then labeled to generate biotinylated cRNA in vitro and amplified using the BioArray T7 RNA polymerase labeling kit (Enzo, Farmingdale, NY).…”

A mouse gene homologous to the Drosophila gene caudal is expressed in epithelial cells from the embryonic intestine.

“…The Hox-l.3 (Dony and Gruss 1987), Hox-2.1 (Holland and Hogan 1988), Hox-5.1 (Featherstone et al 1988), and Hox-6.1 (Sharpe et al 1988) are expressed in the mesoderm-derived tissues of the gut, but not in the endoderm-derived portion. The Hox-l.6 gene is also expressed in intestine, although the precise location of transcripts has not been determined (Baron et al 1987).…”

“…Consistent with the hypothesis that murine 3Present address: INSERM U. 257, Institut Jacques-Monod, Universit~ Paris VII, 75005 Paris, France homeo-box-containing (Hox) genes may regulate aspects of embryogenesis, the expression of Hox genes is restricted temporally and spatially during embryogenesis (Awgulewitsch et al 1986;Gaunt et al 1986;Dony and Gruss 1987;Gaunt 1987;Toth et al 1987;Utset et al 1987;Breier et al 1988;Featherstone et al 1988;Holland and Hogan 1988;Le Mouellic et al 1988;Sharpe et al 1988; for review, see Dressler and Gruss 1988). The regulatory potential of the homeo box genes is further substantiated by their ability to bind DNA (Desplan et al 1985;Fainsod et al 1986;Hoey and Levine 1988) and their nuclear localization (Odenwald et al 1987;Schulze et al 1987).…”

The mouse Hox-1.3 gene is functionally equivalent to the Drosophila Sex combs reduced gene.

“…In very early embryos, it is expressed in nearly all cells (Tani et al 1989). In mid-gestation embryos, Hox-1.3 mRNA is expressed at high levels in the mesoderm and neuroectoderm with an anterior boundary near the junction of the hindbrain and spinal cord (Dony and Gruss 1987;Fibi et al 1988). In adults, the mRNA and protein have also been detected in some tissues, including liver, lung, kidney, and central nervous system (Odenwald et al 1987;Garbem et al 1989).…”