| First Author | Koike S | Year | 1995 |
| Journal | Proc Natl Acad Sci U S A | Volume | 92 |
| Issue | 23 | Pages | 10624-8 |
| PubMed ID | 7479853 | Mgi Jnum | J:29676 |
| Mgi Id | MGI:77201 | Doi | 10.1073/pnas.92.23.10624 |
| Citation | Koike S, et al. (1995) Identification of a DNA element determining synaptic expression of the mouse acetylcholine receptor delta-subunit gene. Proc Natl Acad Sci U S A 92(23):10624-8 |
| abstractText | mRNAs for acetylcholine receptor genes are highly concentrated in the endplate region of adult skeletal muscle largely as a result of a transcription restricted to the subneural nuclei. To identify the regulatory elements involved, we employed a DNA injection of a plasmid containing a fragment of the acetylcholine receptor delta-subunit gene promoter (positions -839 to +45) linked to the reporter gene lacZ with a nuclear localization signal. Injection of the wild-type construct into mouse leg muscles yielded preferential expression of the reporter gene in the synaptic region. Analysis of various mutant promoters resulted in the identification of a DNA element (positions -60 to -49), referred to as the N box, that plays a critical role in subneural expression. Disruption of this 12-bp element in the context of a mouse delta-subunit promoter from positions -839 to +45 gives widespread expression of the reporter gene throughout the entire muscle fiber, indicating that this element is a silencer that represses delta-subunit gene transcription in extrajunctional areas. On the other hand, this element inserted upstream of a heterologous basal promoter preferentially enhances expression in the endplate region. This element therefore regulates the restricted expression of the delta-subunit gene both as an enhancer at the endplate level and as a silencer in extrajunctional areas. Furthermore, gel-shift experiments with mouse muscle extracts reveal an activity that specifically binds the 6-bp sequence TTCCGG of this element, suggesting that a transcription factor(s) controls the expression of the delta-subunit gene via this element. |
