D-six4 plays a key role in patterning cell identities deriving from the Drosophila mesoderm

Abstract

Patterning of the Drosophila embryonic mesoderm requires the regulation of cell type-specific factors in response to dorsoventral and anteroposterior axis information. For the dorsoventral axis, the homeodomain gene, tinman, is a key patterning mediator for dorsal mesodermal fates like the heart. However, equivalent mediators for more ventral fates are unknown. We show that D-six4, which encodes a Six family transcription factor, is required for the appropriate development of most cell types deriving from the non-dorsal mesoderm - the fat body, somatic cells of the gonad, and a specific subset of somatic muscles. Misexpression analysis suggests that D-Six4 and its likely cofactor, Eyes absent, are sufficient to impose these fates on other mesodermal cells. At stage 10, the mesodermal expression patterns of D-six4 and tin are complementary, being restricted to the dorsal and non-dorsal regions respectively. Our data suggest that D-six4 is a key mesodermal patterning mediator at this stage that regulates a variety of cell-type-specific factors and hence plays an equivalent role to tin. At stage 9, however, D-six4 and tin are both expressed pan-mesodermally. At this stage, tin function is required for full D-six4 expression. This may explain the known requirement for tin in some non-dorsal cell types.

Fibroblast growth factor signalling controls successive cell behaviours during mesoderm layer formation in Drosophila

“…This is comparable with the migration speeds of other Drosophila cells that move in collectives, e.g. ovarian border cells [21-60 mm/h (Bianco et al, 2007;Prasad and Montell, 2007;Tekotte et al, 2007)] and male-specific SGPs [(12.3 mm/h) (Clark et al, 2006)]. The mean migration rates of DECs were significantly lower in pyr 18 homozygous mutants (21.4±4.1 mm/h; n=9; two embryos),…”

SIX2 and BMP4 Mutations Associate With Anomalous Kidney Development

“…This finding is consistent with recently published data implicating D-six4 in embryonic mesodermal patterning in Drosophila. 17 Overexpression of bmp4 resulted in ventralization, which confirms a role of bmp4 in ventral mesendoderm formation (Table 2; Figure 4). 13,14 To assay the function of mutated Six2.1 and Bmp4, the human mutations were introduced into cDNA constructs of bmp4 and six2.1 by site-directed mutagenesis.…”

The origin of islet-like cells in Drosophila identifies parallels to the vertebrate endocrine axis

“…3d). The D-six4 gene also shows expression specific to this domain (18,19). Our labeling studies showed that this domain is subdivided into several small compartments of 2-12 cells with discrete gene expression profiles (see Fig.…”