THE WINGED HELIX TRANSCRIPTIONAL ACTIVATOR HFH-8 IS EXPRESSED IN THE MESODERM OF THE PRIMITIVE STREAK STAGE OF MOUSE EMBRYOS AND ITS CELLULAR DERIVATIVES
Rs. Peterson et al., THE WINGED HELIX TRANSCRIPTIONAL ACTIVATOR HFH-8 IS EXPRESSED IN THE MESODERM OF THE PRIMITIVE STREAK STAGE OF MOUSE EMBRYOS AND ITS CELLULAR DERIVATIVES, Mechanisms of development, 69(1-2), 1997, pp. 53-69
The hepatocyte nuclear factor 3/fork head homolog (HFH) proteins are a
n extensive family of transcription factors which share homology in th
e winged helix DNA binding domain. Members of the winged helix family
have been implicated in cell fate determination during pattern formati
on, in organogenesis and in cell type-specific gene expression. In thi
s study, we used in situ hybridization to identify the cellular expres
sion pattern of the winged helix transcription factor, HFH-8, during m
ouse embryonic development. We showed that HFH-8 expression initiates
during the primitive streak stage of mouse embryogenesis in the extrae
mbryonic mesoderm and in the lateral mesoderm which gives rise to the
somatopleuric and splanchnopleuric mesoderm. During organogenesis, HFH
-8 expression is found in the splanchnic mesoderm in close apposition
of the gut endoderm, suggesting a role in mesenchymal-epithelial induc
tion of lung and gut morphogenesis. HFH-8 expression continues in late
ral mesoderm-derived tissue throughout mouse development. HFH-8 expres
sion is observed in the mesenchymal cells of the oral cavity, esophagu
s, trachea, lung, intestine, dorsal aorta and intersomitic arteries, b
ut not in the vasculature of the head, liver, kidney or heart. Consist
ent with these embryonic expression studies, adult HFH-8 expression is
restricted to the endothelium and connective fibroblasts of the alveo
lar sac and in the lamina propria and smooth muscle of the intestine.
We also show that several adult endothelial cell lines maintain abunda
nt HFH-8 expression. Furthermore, we used our determined HFH-8 consens
us sequence to identify putative target genes expressed in pulmonary a
nd intestinal mesenchymal cells. Cotransfection assays with one of the
se target promoters, P-selectin, demonstrated that HFH-8 expression wa
s required for IL-6 stimulation of P-selectin promoter activity and su
ggest that HFH-8 is involved in mediating its cell-specific transcript
ional activation in response to cytokines. (C) 1997 Elsevier Science I
reland Ltd.