Conserved overlapping and reciprocal expression of msh/Msx1 and apterous/Lhx2 in Drosophila and mice

Abstract

Here we describe and compare the expression patterns of the murine genes Lhx2 and Msx1 and their Drosophila orthologues apterous (ap) and muscle-segment homeobox (msh). We find that Lhx2 and Msx1 show complementary patterns of expression in most tissues including the neural and cranial epithelium, pituitary gland, olfactory organs, and neural tube; in contrast, Lhx2 and Msx1 are coexpressed in the developing limbs. Strikingly, the spatial relationship between ap and msh expression in Drosophila is very reminiscent of the expression of their murine orthologues. ap and msh show complementary expression in the leg and antennal imaginal discs, brain and ventral ganglion of the central nervous system (CNS), but both are coexpressed in the wing imaginal disc. These observations suggest conservation in the regulation of these genes between Drosophila and mice.

Molecular Cloning and Characterization of Porcine Homeodomain Transcription Factor Msx1

“…It has been reported that Msx1 participates in developmental regulation of the melatonin- [36] and GnRH receptors [37] in the fetal pituitary. Expression of Msx1 has been observed at embryonic day 11 in the Rathke's pouch, a primordium of the pituitary, by in situ hybridization [38]. The present study demonstrated the expression profile of porcine Msx1 during pituitary development and showed that Msx1 is already expressed at f40 and decreases after birth to an extremely low or undetectable level, indicating that notable Msx1 expression at an early stage is important for pituitary organogenesis.…”

A Network of Transcription Factors Operates during Early Tooth Morphogenesis

“…During molar tooth development, both Lhx6 and Lhx8 are expressed in the dental mesenchyme at the bud stage, and like Msx1 mutant mice, Lhx6 Lhx8 double mutant mice lack molar teeth due to the failure of specification of the molar mesenchyme (Table 1) (52). In vitro studies have shown that Msx1 can physically interact with Lhx2 in the context of limb development, similar to their Drosophila melanogaster orthologues, muscle segment homeobox (msh) and apterous (ap) (54).…”

LIM homeobox transcription factor Lhx2 inhibits skeletal muscle differentiation in part via transcriptional activation of Msx1 and Msx2

“…It was reported that Lhx2, Msx1 and Msx1 mRNAs are highly expressed in the limb buds of developing mouse embryos [12,13,22]. To investigate whether Lhx2 acts upstream of Msx1 and Msx2 genes, we performed siRNA-mediated knockdown of Lhx2 in the organ culture of limb buds.…”

“…In Drosophila, apterous, a functional homolog of mouse Lhx2 [10], has been shown to be essential for muscle development [11]. In mice, Lhx2 mRNA is abundantly expressed in developing limb buds of mouse embryos [12], and the outgrowth of limb buds is accompanied by proliferation and differentiation of myoblasts in the paraxial mesoderm. Although Lhx2-deficient mice exhibit normal limb development, Tzchori et al showed that Lhx2/Lhx9 double knockout mice display severe limb defects leading to shortened digits [13], which is consistent with the finding that cLhx2 is required for limb outgrowth in the chick [14].…”