title: Two novel transcripts for human endothelin B receptor produced by RNA editing/alternative splicing from a single gene.
abstract: Hirschsprung disease is a heterogeneous genetic disorder, causative genes of which include the endothelin B receptor (ETB). To investigate the mutations of ETB in Hirschsprung disease, expression of the ETB gene in lymphoblastoid cells from patients and normal healthy adults was examined, and novel mutant transcripts were found. The mutant ETB gene transcripts lacked a 134-bp nucleotide sequence corresponding to exon 5, and some also contained a substitution from A to G at position 950 in exon 4, resulting in an amino acid substitution from glutamine (Q) to arginine (R). This substitution was suspected to be the result of RNA editing because it was not present in the genomic sequence. Transfection experiments using ETB minigenes containing the editing site with or without the gene for double-strand RNA deaminases (ADAR1 and ADAR2) revealed that the deaminases were involved in RNA editing. Furthermore, a c-Myc-tagged mutant ETB protein was not detected by Western blot analysis. The present results show that the mutant ETB transcripts were novel splice variants, which might not be translated, or that the products translated from splice variants might be quickly degraded, presumably because of their instability. The preferential production of this null function ETB by RNA editing/splicing could be involved in the etiology of some cases of Hirschsprung disease.
authors.affiliation: Department of Molecular, Cell Pharmacology, National Center for Child Health and Development Research Institute 3-35-31, Taishi-do, Setagaya-Ku, Tokyo 154-8567, Japan.
authors.forename: Akito
authors.initials: A
authors.lastname: Tanoue
authors.forename: Taka-Aki
authors.initials: TA
authors.lastname: Koshimizu
authors.forename: Masako
authors.initials: M
authors.lastname: Tsuchiya
authors.forename: Kayano
authors.initials: K
authors.lastname: Ishii
authors.forename: Makiko
authors.initials: M
authors.lastname: Osawa
authors.forename: Morihiro
authors.initials: M
authors.lastname: Saeki
authors.forename: Gozoh
authors.initials: G
authors.lastname: Tsujimoto
mesh_terms: D000483:Alleles; D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D019556:COS Cells; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D000939:Epitopes; D005091:Exons; D006627:Hirschsprung Disease / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000494:pharmacology; D010957:Plasmids / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D017393:RNA Editing; D012333:RNA, Messenger / Q000378:metabolism*; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D018076:DNA, Complementary; D000939:Epitopes; D009841:Oligonucleotides; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin