HNF-6 is expressed in endoderm derivatives and nervous system of the mouse embryo and participates to the cross-regulatory network of liver-enriched transcription factors

Abstract

Hepatocyte nuclear factor-6 (HNF-6) is a liver-enriched transcription factor that contains a single cut domain and a novel type of homeodomain. Here we have studied the developmental expression pattern of HNF-6 in the mouse. In situ hybridization experiments showed that HNF-6 mRNA is detected in the liver at embryonic day (E) 9, at the onset of liver differentiation. HNF-6 mRNA disappeared transiently from the liver between E12.5 and E15. In transfection experiments HNF-6 stimulated the expression of HNF-4 and of HNF-3 beta, two transcription factors known to be involved in liver development and differentiation. HNF-6 was detected in the pancreas from E10.5 onward, where it was restricted to the exocrine cells. HNF-6 was also detected in the developing nervous system. Both the brain and the spinal cord started to express HNF-6 at E9-9.5 in postmitotic neuroblasts. Later on, HNF-6 was restricted to brain nuclei, to the retina, to the ventral horn of the spinal cord, and to dorsal root ganglia. Our observations that HNF-6 contributes to the control of the expression of transcription factors and is expressed at early stages of liver, pancreas, and neuronal differentiation suggest that HNF-6 regulates several developmental programs.