| First Author | Li Y | Year | 1994 |
| Journal | J Biol Chem | Volume | 269 |
| Issue | 44 | Pages | 27589-94 |
| PubMed ID | 7961675 | Mgi Jnum | J:21241 |
| Mgi Id | MGI:69265 | Doi | 10.1016/s0021-9258(18)47025-1 |
| Citation | Li Y, et al. (1994) Regulation of alpha o expression by the 5'-flanking region of the alpha o gene. J Biol Chem 269(44):27589-94 |
| abstractText | Many responses of cells to external signals require activation of the heterotrimeric G proteins. These responses depend on the type and amount of G proteins that are expressed. Each cell has a characteristic complement of G protein subunits. For example, the alpha o subunit is very abundant in neural tissues. Very little is known about the mechanisms that determine cellular levels of G proteins. In the present study, we have isolated a genomic clone for mouse alpha o gene and identified the promoter region. There are multiple transcription initiation sites located about 750 base pairs upstream of the translational start site. The promoter region is GC-rich and contains neither a TATA-box nor a CAAT box. Transient expression assays using a series of constructs containing various lengths of the 5'-flanking region of the alpha o promoter demonstrated that the region 300-700 base pairs upstream of the transcription initiation sites is responsible for the basic promoter activity. The relative activity of alpha o promoter is 8-12-fold higher in cells expressing alpha o than in cells lacking alpha o. The level of alpha o in cells may also be regulated at the level of protein translation because deletions in the 5'-noncoding region of alpha o gene increase reporter enzyme expression without a corresponding increase in reporter enzyme mRNA level. Our results suggest that both transcriptional and post-transcriptional mechanisms are involved in regulating the expression of alpha o in vivo. Transcriptional regulation probably is important for control of tissue-specific expression, while posttranscriptional mechanisms may be used to regulate the alpha o level in cells. |
