The transcription factor Bhlhb4 is required for rod bipolar cell maturation.
Retinal bipolar cells are essential to the transmission of light information. Although bipolar cell dysfunction can result in blindness, little is known about the factors required for bipolar cell development and functional maturation. The basic helix-loop-helix (bHLH) transcription factor Bhlhb4 was found to be expressed in rod bipolar cells (RB). Electroretinograms (ERGs) in the adult Bhlhb4 knockout (Bhlhb4(-/-)) showed that the loss of Bhlhb4 resulted in disrupted rod signaling and profound retinal dysfunction resembling human congenital stationary night blindness (CSNB), characterized by the loss of the scotopic ERG b-wave. A depletion of inner nuclear layer (INL) cells in the adult Bhlhb4 knockout has been ascribed to the abolishment of the RB cell population during postnatal development. Other retinal cell populations including photoreceptors were unaltered. The timing of RB cell depletion in the Bhlhb4(-/-) mouse suggests that Bhlhb4 is essential for RB cell maturation.
Pubmed ID: 15363390 RIS Download
Age Factors | Animals | Animals, Newborn | Basic Helix-Loop-Helix Transcription Factors | Blotting, Southern | Calbindin 2 | Calbindins | Calcium-Binding Proteins | Caspase 3 | Caspases | Cell Aging | Cell Count | Cells, Cultured | Electroretinography | Embryo, Mammalian | Evoked Potentials | Eye Proteins | Fluorescent Antibody Technique | GTP-Binding Protein alpha Subunits, Gi-Go | Gene Expression | Gene Expression Regulation, Developmental | Homeodomain Proteins | In Situ Hybridization | Indenes | Membrane Glycoproteins | Membrane Transport Proteins | Mice | Mice, Knockout | Microscopy, Electron | Nerve Tissue Proteins | Neurons | PAX6 Transcription Factor | Paired Box Transcription Factors | Photic Stimulation | Protein Kinase C | Protein Kinase C-alpha | RNA, Messenger | Repressor Proteins | Retina | Retinal Rod Photoreceptor Cells | Reverse Transcriptase Polymerase Chain Reaction | S100 Calcium Binding Protein G | S100 Proteins | Stem Cells | Synapses | Transcription Factors | Vesicular Glutamate Transport Protein 1 | Vesicular Transport Proteins | beta-Galactosidase