Cloning of rat laminin gamma 1-chain gene promoter reveals motifs for recognition of multiple transcription factors

• Published in: American journal of physiology. Renal physiology Vol. 273; no. 3 Pt 2; pp. F411 - F420
• Main Authors: O'Neill, B C, Suzuki, H, Loomis, W P, Denisenko, O, Bomsztyk, K
• Format: Journal Article
• Language: English
• Published: United States 01.09.1997
• Subjects: Animals; Base Sequence; Binding Sites; Cell Line; Cloning, Molecular; Genomic Library; Humans; Kidney - metabolism; Laminin - biosynthesis; Laminin - genetics; Mice; Molecular Sequence Data; Polymerase Chain Reaction; Promoter Regions, Genetic; Rats; Rats, Sprague-Dawley; Sequence Alignment; Sequence Homology, Nucleic Acid; TATA Box; Transcription Factors - metabolism
• ISSN: 0002-9513; 1931-857X; 1522-1466
• DOI: 10.1152/ajprenal.1997.273.3.F411

We have previously shown that laminin gamma 1 (laminin B2)-chain mRNA levels increase in response to treatment of rat glomerular epithelial cells (GEC) with the cytokine interleukin-1 beta (IL-1 beta) [C. A. Richardson, K. L. Gordon, W. G. Couser, and K. Bomsztyk. Am. J. Physiol. 268 (Renal Fluid Electrolyte Physiol. 37): F273-F278, 1995]. IL-1 beta-induced increase in laminin gamma 1-chain gene expression is likely to be transcriptionally regulated. As the laminin gamma 1-chain gene promoter had not previously been cloned in the rat, we cloned the 5'-flanking region of this gene from a rat genomic library. Like the human and murine laminin gamma 1-chain gene promoters, the rat laminin gamma 1-chain gene fragment spanning from nucleotides -1104 to +109, relative to the start codon, is "GC" rich and lacks TATA or CAAT boxes. This rat laminin gamma 1-chain gene promoter region appears to contain at least two transcription initiation sites, i.e., position -169 and -234. In transient transfections in GEC, the -1104/+35 and -1104/-15 fragments cloned upstream of a luciferase reporter gene had very little constitutive activity and were not IL-1 beta responsive. In sharp contrast, a -1104/-234 fragment exhibited constitutive activity and was IL-1 beta responsive. The -1104/-234 fragment contains motifs that recognize Sp1, BCN-1, and ApoE-B1-AP1 DNA-binding activities in GEC nuclear extracts. Collectively, the results of this study suggest that multiple inducible transcription factors may regulate laminin gamma 1-chain gene promoter activity in GEC.