Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 1992 Oct 11;20(19):5105-13.
doi: 10.1093/nar/20.19.5105.

Different E-box regulatory sequences are functionally distinct when placed within the context of the troponin I enhancer

K E Yutzey  1 , S F Konieczny
Affiliations
Free PMC article
Comparative Study

Different E-box regulatory sequences are functionally distinct when placed within the context of the troponin I enhancer

K E Yutzey et al. Nucleic Acids Res. .
Free PMC article

Abstract

Basic helix-loop-helix (bHLH) regulatory proteins are known to bind to a single DNA consensus sequence referred to as an E-box. The E-box is present in the regulatory elements of many developmentally controlled genes, including most muscle-specific genes such as troponin I (TnI). Although the E-box consensus is minimally defined as CANNTG, the adjacent nucleotides of functional E-boxes are variable for genes regulated by the bHLH proteins. In order to examine how E-box regulatory regions containing different internal and flanking nucleotides function when placed within the context of a single regulatory element, the E-box region (14 bp) present within the TnI enhancer was substituted with the corresponding E-box sequences derived from the muscle-specific M-creatine kinase (MCK) and cardiac alpha-actin regulatory elements as well as from the immunoglobulin kappa (Ig kappa) enhancer. Within the TnI enhancer, the E-box sequence derived from cardiac alpha-actin was inactive whereas the corresponding sequence from the MCK right E-box efficiently restored wild-type enhancer activity in muscle cells. Intermediate levels of gene activity were observed for TnI enhancers containing E-boxes derived from the MCK left E-box site or from the Ig kappa E2 E-box. DNA binding studies of MyoD:E12 protein complexes with each substituted TnI enhancer confirmed that DNA binding activity in vitro mimics the relative strength of the enhancers in vivo. These studies demonstrate that the specific nucleotide composition of individual E-boxes, which are contained within the regulatory elements of most if not all muscle-specific genes, contributes to the complex regulatory mechanisms governing bHLH-mediated gene expression.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. DNA. 1985 Apr;4(2):165-70 - PubMed
    1. Cell. 1987 Dec 24;51(6):987-1000 - PubMed
    1. Mol Cell Biol. 1982 Sep;2(9):1044-51 - PubMed
    1. Science. 1990 Nov 23;250(4984):1104-10 - PubMed
    1. Nucleic Acids Res. 1990 Nov 11;18(21):6239-46 - PubMed

Publication types

MeSH terms