title: Spatial, temporal and subcellular localization of islet-brain 1 (IB1), a homologue of JIP-1, in mouse brain.
abstract: Islet-brain 1 (IB1) was recently identified as a DNA-binding protein of the GLUT2 gene promoter. The mouse IB1 is the rat and human homologue of the Jun-interacting protein 1 (JIP-1) which has been recognized as a key player in the regulation of c-Jun amino-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways. JIP-1 is involved in the control of apoptosis and may play a role in brain development and aging. Here, IB1 was studied in adult and developing mouse brain tissue by in situ hybridization, Northern and Western blot analysis at cellular and subcellular levels, as well as by immunocytochemistry in brain sections and cell cultures. IB1 expression was localized in the synaptic regions of the olfactory bulb, retina, cerebral and cerebellar cortex and hippocampus in the adult mouse brain. IB1 was also detected in a restricted number of axons, as in the mossy fibres from dentate gyrus in the hippocampus, and was found in soma, dendrites and axons of cerebellar Purkinje cells. After birth, IB1 expression peaks at postnatal day 15. IB1 was located in axonal and dendritic growth cones in primary telencephalon cells. By biochemical and subcellular fractionation of neuronal cells, IB1 was detected both in the cytosolic and membrane fractions. Taken together with previous data, the restricted neuronal expression of IB1 in developing and adult brain and its prominent localization in synapses suggest that the protein may be critical for cell signalling in developing and mature nerve terminals.
authors.affiliation: Institut de Biologie Cellulaire et de Morphologie, IBCM, Rue du Bugnon 9, 1005 Lausanne, Switzerland.
authors.forename: J B
authors.initials: JB
authors.lastname: Pellet
authors.forename: J A
authors.initials: JA
authors.lastname: Haefliger
authors.forename: J K
authors.initials: JK
authors.lastname: Staple
authors.forename: C
authors.initials: C
authors.lastname: Widmann
authors.forename: E
authors.initials: E
authors.lastname: Welker
authors.forename: H
authors.initials: H
authors.lastname: Hirling
authors.forename: C
authors.initials: C
authors.lastname: Bonny
authors.forename: P
authors.initials: P
authors.lastname: Nicod
authors.forename: S
authors.initials: S
authors.lastname: Catsicas
authors.forename: G
authors.initials: G
authors.lastname: Waeber
authors.forename: B M
authors.initials: BM
authors.lastname: Riederer
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001921:Brain / Q000196:embryology / Q000254:growth & development; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000737:chemistry; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism; D005136:Eye Proteins / Q000032:analysis; D005326:Fetal Proteins / Q000032:analysis; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D048031:JNK Mitogen-Activated Protein Kinases; D020935:MAP Kinase Signaling System; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009687:Nuclear Proteins / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D009928:Organ Specificity; D020033:Protein Isoforms / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000737:chemistry / Q000254:growth & development; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity; D013347:Subcellular Fractions / Q000737:chemistry; D013687:Telencephalon / Q000166:cytology / Q000378:metabolism; D015534:Trans-Activators / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D005136:Eye Proteins; D005326:Fetal Proteins; C490666:MAPK8IP1 protein, human; C490665:Mapk8ip protein, mouse; C110528:Mapk8ip1 protein, rat; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D015534:Trans-Activators; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases