Drosophila JAB1/CSN5 acts in photoreceptor cells to induce glial cells.

Different classes of photoreceptor neurons (R cells) in the Drosophila compound eye form connections in different optic ganglia. The R1-R6 subclass connects to the first optic ganglion, the lamina, and relies upon glial cells as intermediate targets. Conversely, R cells promote glial cell development including migration of glial cells into the target region.

A set of polyclonal and monoclonal antibodies reveals major differences in post-translational modification of the rat HNF1 and vHNF1 homeoproteins.

The related homeodomain-containing transcription factors HNF1 (HNF1 alpha) and vHNF1 (HNF1 beta) recognise common target DNA sequences in the regulatory regions of many genes and are expressed in several parenchymal cell types, predominantly in liver, kidney, intestine and pancreas. HNF1-null mutant mice, with a wild-type vHNF1 gene, develop normally, but die within a few weeks of birth with severe liver and kidney failure. Humans with a mutation in the HNF1 alpha gene develop non-insulin dependent diabetes on maturity (MODY 3).

A hepatitis B virus mutant with a new hepatocyte nuclear factor 1 binding site emerging in transplant-transmitted fulminant hepatitis B.

Hepatitis B virus (HBV) DNA was cloned from serum of a heart transplant recipient who died from fulminant hepatitis B transmitted by the donor. Restriction enzyme analyses of the clones obtained by conventional cloning yielded six HBV variants: a major species (pF-1) representing 88% and five minor species (pF-2 to pF-6), each representing 2% to 4% of the clones. The complete nucleotide sequence of these six variants revealed that five of the six viral genomes, including pF-1, carried a novel 11 base pair (bp) insertion in the core promoter region as well as an 18 bp and an 108 bp in-frame deletion in the pre-S1 region not present in the donor.

The HNF1 C-terminal domain contributes to transcriptional activity and modulates nuclear localisation.

HNF1 is a homeoprotein that regulates the expression of a large number of liver specific genes. By performing transient expression assays with a series of C-terminal deletion mutants and with a LexA-HNF1 fusion protein, we show that the C-terminal half of HNF1 is necessary and sufficient for in vivo transcriptional activity, and we map the residues essential for this activity. However, since our data for some mutants showed discrepancies with previous in vitro studies, we undertook a more careful analysis of the mutant proteins using gel retardation assays and immunoblots made with nuclear extracts from transfected cells.

Hepatic nuclear factor 1 (HNF1) shows a wider distribution than products of its known target genes in developing mouse.

Hepatic nuclear factor 1 (HNF1) is a highly diverged homeoprotein that is crucial for transcription of many liver-specific genes including albumin. In particular, a minimal promoter, consisting of an HNF1-binding-site and a TATA box, is highly active only in hepatoma cell lines. The expression of the HNF1 and albumin genes has been examined in mouse embryos by in situ hybridization.

vHNF1 is a homeoprotein that activates transcription and forms heterodimers with HNF1.

vHNF1 and HNF1 are two nuclear proteins that bind to an essential element in the promoter proximal sequences of albumin and of many other liver-specific genes. HNF1 predominates in hepatocytes but is absent in dedifferentiated hepatoma cells. These cells contain vHNF1 but fail to express most of the liver traits.

A distal dimerization domain is essential for DNA-binding by the atypical HNF1 homeodomain.

Hepatic Nuclear Factor 1 (HNF1, also referred to as LFB1, HP1 or APF) is a liver-specific transcription factor required for the expression of many hepatocyte specific genes. We report here the purification of this rat liver nuclear protein and the cloning of its cDNA using a PCR-derived approach. Seven independent clones reveal 3 alternative polyadenylation sites and a unique open reading frame.