Characterization of the Transcription Unit of Mouse Kv1.4, a Voltage-gated Potassium Channel Gene
| Autor: | K. Kalman, Jayashree Aiyar, Deborah Negulescu, George A. Gutman, Randy S. Wymore, K. George Chandy, Keith D. Kinoshita |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Potassium Channels
Transcription Genetic Polyadenylation Restriction Mapping Biology Biochemistry Membrane Potentials Mice Xenopus laevis Exon Start codon Transcription (biology) Animals Coding region Tissue Distribution RNA Messenger Promoter Regions Genetic Molecular Biology Gene Messenger RNA Base Sequence 3T3 Cells Cell Biology Molecular biology Stop codon Enhancer Elements Genetic Gene Expression Regulation Genes Protein Biosynthesis Oocytes |
| Zdroj: | Journal of Biological Chemistry. 271:15629-15634 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.271.26.15629 |
| Popis: | The mouse voltage-gated K+ channel gene, Kv1.4, is expressed in brain and heart as approximately 4.5- and approximately 3.5-kilobase (kb) transcripts. Both mRNAs begin at a common site 1338 bp upstream of the initiation codon, contain 3477 and 4411 nucleotides, respectively, and are encoded by two exons; exon 1 contains 0.5 kb of the 5'-noncoding region (NCR), while exon 2 encodes the remaining 0.8 kb of the 5'-NCR, the entire coding region (2 kb), and all of the 3'-NCR. The 3.5-kb transcript terminates at a polyadenylation signal 177 bp 3' of the stop codon, while the 4.5-kb mRNA utilizes a signal 94 bp farther downstream. Although the proteins generated from either transcript are identical, the two mRNAs are functionally different, the 3.5-kb transcript producing approximately 4-5-fold larger currents when expressed in Xenopus oocytes compared to the 4. 5-kb mRNA. The decreased expression of the longer transcript is due to the presence of five ATTTA repeats in the 3'-NCR which inhibit translation; such motifs have also been reported to destabilize the messages of many other genes and might therefore shorten the life of the 4.5-kb transcript during its natural expression. The Kv1.4 basal promoter is GC-rich, contains three SP1 repeats (CCGCCC, -65 to -35), lacks canonical TATAAA and GGCAATCT motifs, and has no apparent tissue specificity. One region enhances activity of this promoter. Thus, transcriptional and post-transcriptional regulation of mKv1.4, coupled with selective usage of the two alternate Kv1.4 mRNAs, may modulate the levels of functional Kv1.4 channels. |
| Databáze: | OpenAIRE |
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