Promoter elements and transcriptional control of the chicken β tropomycin gene

• Published in: Nucleic acids research 1994-05, Vol.22 (10), p.1838-1845
• Main Authors: Toutant, Madeleine, Gauthier-Rouviere, Cécile, Fiszman, Marc Y., Lemonnier, Marguerite
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Molecular and cellular biology; Molecular genetics; Transcription. Transcription factor. Splicing. Rna processing
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/22.10.1838

The chicken β tropomyosin (βTM) gene has two alternative transcription start sites (sk and nmCAP sites) which are used in muscle or non muscle tissues respectively. In order to understand the mechanisms involved in the tissue-specific and developmentally-regulated expression of the βTM gene, we have analyzed the 5′ regions associated with each CAP site. Truncated regions 5′ to the nmCAP site were inserted upstream to the bacterial chloramphenicol acetyltransferase (CAT) reporter gene and these constructs were transfected into avian myogenic and non myogenic cells. The maximum transcription is driven by the CAT construct (− 168/ + 216 nt) in all cell types. Previous deletion analysis of the region 5′ to the βTMskCAP site has indicated that 805 nt confer myotube-specific transcription. In this work, we characterize an enhancer element (− 201/ − 68 nt) which contains an E box (− 177), a variant CArG box (− 104) and a stretch of 7Cs (− 147). Mutation of any of these motifs results in a decrease of the myotube-specific transcriptional activity. Electrophoretic mobility shift assays indicate that these cis-acting sequences specifically bind nuclear proteins. This enhancer functions in an orientation-dependent manner.