Two Upstream Elements Activate Transcription of a Major Histocompatibility Complex Class I Gene in Vitro
Overview
Authors
Affiliations
Expression of major histocompatibility complex (MHC) class I genes exhibits unique tissue and developmental specificity. In an effort to study molecular mechanisms of MHC class I gene regulation, an in vitro transcription system has been established. In B cell nuclear extracts a template DNA containing the mouse H-2Ld promoter sequence accurately directed RNA polymerase II-dependent transcription of a G-free cassette. A conserved class I regulatory complex previously shown to moderately enhance promoter activity in vivo enhanced transcription in vitro by 2-3 fold. Much of this enhancement was accounted for by a 40 bp fragment within the complex, which was capable of activating a basal H-2Ld promoter in either orientation. Farther downstream, another element called site B was identified, which independently activated MHC class I transcription in vitro by 2-4 fold. Site B bound a specific nuclear factor(s) through an NF-1 binding site but not through a neighboring CCAAT site. The functional significance of site B in vivo was demonstrated in transfection experiments in which site B enhanced MHC class I promoter activity to a degree comparable to that seen in vitro. With the identification of the two upstream activators, MHC class I genes may serve as a model to study roles of sequence-specific DNA-binding proteins in transcription in vitro.
The Child with Recurrent Mycobacterial Disease.
Reed B, Dolen W Curr Allergy Asthma Rep. 2018; 18(8):44.
PMID: 29936646 DOI: 10.1007/s11882-018-0797-3.
Expression of nonclassical MHC class Ib genes: comparison of regulatory elements.
Howcroft T, Singer D Immunol Res. 2003; 27(1):1-30.
PMID: 12637766 DOI: 10.1385/IR:27:1:1.
Ronco L, Karpova A, Vidal M, Howley P Genes Dev. 1998; 12(13):2061-72.
PMID: 9649509 PMC: 316980. DOI: 10.1101/gad.12.13.2061.
Wang I, Blanco J, Tsai S, Tsai M, Ozato K Mol Cell Biol. 1996; 16(11):6313-24.
PMID: 8887661 PMC: 231634. DOI: 10.1128/MCB.16.11.6313.
Segars J, Nagata T, Bours V, Medin J, Franzoso G, Blanco J Mol Cell Biol. 1993; 13(10):6157-69.
PMID: 8413217 PMC: 364675. DOI: 10.1128/mcb.13.10.6157-6169.1993.