title: The transcription factor Bhlhb4 is required for rod bipolar cell maturation.
abstract: 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.
authors.affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA. debrab@bcm.tmc.edu
authors.forename: Debra E
authors.initials: DE
authors.lastname: Bramblett
authors.forename: Mark E
authors.initials: ME
authors.lastname: Pennesi
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Wu
authors.forename: Ming-Jer
authors.initials: MJ
authors.lastname: Tsai
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D051792:Basic Helix-Loop-Helix Proteins; D015139:Blotting, Southern / Q000379:methods; D064032:Calbindin 2; D064026:Calbindins; D002135:Calcium-Binding Proteins / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002452:Cell Count; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology*; D004596:Electroretinography / Q000379:methods; D004622:Embryo, Mammalian; D005071:Evoked Potentials / Q000235:genetics / Q000528:radiation effects; D005136:Eye Proteins; D005455:Fluorescent Antibody Technique / Q000379:methods; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000378:metabolism; D017403:In Situ Hybridization; D007192:Indenes / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D051379:Mice; D018345:Mice, Knockout; D008854:Microscopy, Electron / Q000379:methods; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D010775:Photic Stimulation / Q000379:methods; D011493:Protein Kinase C / Q000378:metabolism; D051571:Protein Kinase C-alpha; D012333:RNA, Messenger / Q000096:biosynthesis; D012097:Repressor Proteins; D012160:Retina / Q000166:cytology* / Q000196:embryology / Q000648:ultrastructure; D017948:Retinal Rod Photoreceptor Cells / Q000196:embryology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism; D013234:Stem Cells / Q000502:physiology*; D013569:Synapses / Q000502:physiology / Q000648:ultrastructure; D014157:Transcription Factors / Q000502:physiology*; D050598:Vesicular Glutamate Transport Protein 1; D033921:Vesicular Transport Proteins / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D064032:Calbindin 2; D064026:Calbindins; D002135:Calcium-Binding Proteins; D053148:Caspase 3; D020169:Caspases; D005136:Eye Proteins; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D018398:Homeodomain Proteins; D007192:Indenes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D012333:RNA, Messenger; D012097:Repressor Proteins; D064030:S100 Calcium Binding Protein G; D009418:S100 Proteins; D014157:Transcription Factors; D050598:Vesicular Glutamate Transport Protein 1; D033921:Vesicular Transport Proteins; D001616:beta-Galactosidase; C455509:Bhlhb4 protein, mouse; C000605730:PAX6 protein, human; C000605732:Pax6 protein, mouse; C000605733:Pax6 protein, rat; C403704:SV2C protein, rat; C489614:Sv2a protein, mouse; C489618:Sv2a protein, rat; C485753:Sv2c protein, mouse; C002201:DABI; C496630:Prkca protein, mouse; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; C085577:Ca2+-binding protein-1