ABSTRACT
A novel neurotrophic factor named Persephin that is approximately 40% identical to glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) has been identified using degenerate PCR. Persephin, like GDNF and NTN, promotes the survival of ventral midbrain dopaminergic neurons in culture and prevents their degeneration after 6-hydroxydopamine treatment in vivo. Persephin also supports the survival of motor neurons in culture and in vivo after sciatic nerve axotomy and, like GDNF, promotes ureteric bud branching. However, in contrast to GDNF and NTN, persephin does not support any of the peripheral neurons that were examined. Fibroblasts transfected with Ret and one of the coreceptors GFRalpha-1 or GFRalpha-2 do not respond to persephin, suggesting that persephin utilizes additional, or different, receptor components than GDNF and NTN.
Subject(s)
Motor Neurons/chemistry , Nerve Growth Factors/genetics , Nerve Tissue Proteins/genetics , Neuroprotective Agents/metabolism , Animals , Cell Death/physiology , Cell Survival/drug effects , Cells, Cultured , Ganglia, Spinal/cytology , Gene Expression Regulation, Developmental , Glial Cell Line-Derived Neurotrophic Factor , Humans , Mesencephalon/cytology , Mice , Molecular Sequence Data , Motor Neurons/physiology , Neurturin , Nodose Ganglion/cytology , Polymerase Chain Reaction/methods , Rats , Rats, Sprague-Dawley , Receptors, Growth Factor/physiology , Receptors, Retinoic Acid/physiology , Sequence Homology, Amino Acid , Signal Transduction/physiology , Superior Cervical Ganglion/cytology , Transfection , Trigeminal Ganglion/cytology , Ureter/cytology , Ureter/embryologyABSTRACT
The glial cell line-derived neurotrophic factor (GDNF) ligands (GDNF, Neurturin [NTN], and Persephin [PSP]) signal through a multicomponent receptor system composed of a high-affinity binding component (GFRalpha1-GFRalpha4) and a common signaling component (RET). Here, we report the identification of Artemin, a novel member of the GDNF family, and demonstrate that it is the ligand for the former orphan receptor GFRalpha3-RET. Artemin is a survival factor for sensory and sympathetic neurons in culture, and its expression pattern suggests that it also influences these neurons in vivo. Artemin can also activate the GFRalpha1-RET complex and supports the survival of dopaminergic midbrain neurons in culture, indicating that like GDNF (GFRalpha1-RET) and NTN (GFRalpha2-RET), Artemin has a preferred receptor (GFRalpha3-RET) but that alternative receptor interactions also occur.
Subject(s)
Drosophila Proteins , Mesencephalon/physiology , Nerve Growth Factors/physiology , Nerve Tissue Proteins/physiology , Neurons/physiology , Proto-Oncogene Proteins/physiology , Receptor Protein-Tyrosine Kinases/physiology , Signal Transduction/physiology , Superior Cervical Ganglion/physiology , Amino Acid Sequence , Animals , Animals, Newborn , Binding Sites , Cell Survival , Cells, Cultured , Cloning, Molecular , Embryo, Mammalian , Glial Cell Line-Derived Neurotrophic Factor , Glial Cell Line-Derived Neurotrophic Factor Receptors , Humans , Ligands , Mesencephalon/cytology , Mice , Models, Chemical , Molecular Sequence Data , Nerve Growth Factors/chemistry , Nerve Tissue Proteins/chemistry , Neurons/cytology , Proto-Oncogene Proteins c-ret , Rats , Rats, Sprague-Dawley , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Sequence Alignment , Sequence Homology, Amino Acid , Superior Cervical Ganglion/cytologyABSTRACT
The two Nab genes, coding for transcriptional corepressors of NGFI-A (Egr-1, Krox24, zif268) and Krox20, have been localized to two regions of the genome, each of which contains at least two members of the Stat gene family. The association of the two Nab genes with the Stat clusters on mouse chromosomes 1 and 10 (human chromosomes 2 and 12) suggest that a Nab gene was involved in at least one of the duplication events that resulted in dispersion of the primordial Stat gene pair to three different mouse chromosomes. Sequencing of the Nab2 genomic locus revealed that it is situated very close to the Stat6 gene. The transcripts of the two genes converge, such that the 3' ends of the Stat6 and Nab2 mRNAs overlap by 58 bp. Both transcripts terminate within a 78-bp region that is absolutely conserved between mouse and human. Analysis of Nab2 cDNA revealed that there is an alternatively spliced form of the Nab2 transcript (lacking exon 3) that produces a protein that lacks the ability to repress transcription by NGFI-A and Krox20.
Subject(s)
Neoplasm Proteins , Repressor Proteins/genetics , Trans-Activators/genetics , Alternative Splicing , Amino Acid Sequence , Animals , Base Sequence , Chromosome Mapping , Conserved Sequence , DNA Primers/genetics , DNA, Complementary/genetics , Humans , Mice , Molecular Sequence Data , Multigene Family , RNA, Messenger/genetics , RNA, Messenger/metabolism , Repressor Proteins/metabolism , STAT6 Transcription Factor , Species Specificity , Trans-Activators/metabolism , Transcription, GeneticABSTRACT
The nerve growth factor-induced clone C (NGFI-C) gene encodes a zinc-finger transcription factor that is rapidly induced by nerve growth factor in rat pheochromocytoma PC12 cells and by seizure in brain. NGFI-C is closely related to the previously described early response genes, nerve growth factor-induced clone A (NGFI-A or EGR1), EGR2, and EGR3. These four early response (immediate early) proteins all contain very similar zinc-finger DNA binding domains; in addition, analysis of the non-zinc-finger region revealed that they share an additional five highly homologous subdomains, four of which are within the amino terminus. The 5' flanking region of NGFI-C contains several cAMP response elements but does not contain any serum-response elements or CArG boxes [CC(A/T)6GG], cis-acting elements commonly involved in early response gene regulation. NGFI-C mRNA was detected in neural tissues of postnatal animals, but no expression was found in rat embryos. In situ hybridization demonstrated that NGFI-C is rapidly induced in the dentate gyrus of the hippocampus after seizure, but in contrast to NGFI-A, increases in NGFI-C mRNA were not detected in the overlying cortex. By using fluorescence in situ hybridization, NGFI-C was localized to human chromosome 2p13. This region contains a constitutive fragile site that is associated with chromosomal breakpoints and translocations characteristic of some chronic lymphocytic leukemias.
Subject(s)
Brain/physiology , Chromosome Mapping , Chromosomes, Human, Pair 2 , DNA-Binding Proteins/genetics , Transcription Factors/genetics , Zinc Fingers/genetics , Amino Acid Sequence , Animals , Base Sequence , Brain/physiopathology , Chromosome Banding , Genomic Library , Humans , Karyotyping , Male , Molecular Sequence Data , Oligodeoxyribonucleotides , Organ Specificity , PC12 Cells , RNA, Messenger/genetics , RNA, Messenger/metabolism , Seizures/physiopathology , Sequence Homology, Nucleic AcidABSTRACT
We have cloned NGFI-C, a nerve growth factor-induced early-response gene which encodes a Cys2/His2 zinc finger protein. RNA blot analysis demonstrates that NGFI-C mRNA is induced within minutes of stimulation of PC12 cells by nerve growth factor and is similarly activated in brain after a Metrazol-induced seizure. The cDNA sequence predicts a protein that contains three zinc fingers which show striking homology to the DNA-binding regions of three previously reported zinc finger proteins, NGFI-A, Krox-20, and the Wilms' tumor gene product. NGFI-C binds to the previously described DNA-binding site of these three proteins, which is GCGGGGGCG. Cotransfection experiments revealed that NGFI-C strongly activates transcription from this site in mammalian cells. The isolation of another early-response gene that encodes a member of the G(C/G)G or GSG element-binding family should provide an opportunity to investigate the relative contributions of a family of transcription factors to the cell's response to changes in its environment.
