Multiple transcription factors in 5'-flanking region of human polymeric Ig receptor control its basal expression.
The polymeric Ig receptor (pIgR) is a critical component of the mucosal immune system and is expressed in largest amounts in the small intestine. In this study, we describe the initial characterization of the core promoter region of this gene. Expression of chimeric promoter-reporter constructs was supported in Caco-2 and HT-29 cells, and DNase I footprint analysis revealed a large protein complex within the core promoter region. Site-directed mutagenesis experiments determined that elements within this region serve to either augment or repress basal activity of the human pIgR promoter. Band shift assays of overlapping oligonucleotides within the core promoter identified eight distinct complexes; the abundance of most complexes was enhanced in post-confluent cells. In summary, we report the characterization of the human pIgR promoter and the essential role that eight different nuclear complexes have in controlling basal expression of this gene in Caco-2 cells.
Department of Biology, California State University, Northridge 91330, USA.
R Sergio
RS
Solorzano-Vargas
Jiafang
J
Wang
Lingling
L
Jiang
Hugh V
HV
Tsai
Luis O
LO
Ontiveros
Mukta A
MA
Vazir
Renato J
RJ
Aguilera
Martín G
MG
Martín
D000818:Animals; D001483:Base Sequence / Q000235:genetics; D016466:CHO Cells; D018938:Caco-2 Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D018983:DNA Footprinting; D004586:Electrophoresis; D017930:Genes, Reporter; D019073:HT29 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D019056:Receptors, Polymeric Immunoglobulin / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000502:physiology*; D014162:Transfection
D019056:Receptors, Polymeric Immunoglobulin; D014157:Transcription Factors