PUBLICATION
Lmx1b and FoxC Combinatorially Regulate Podocin Expression in Podocytes
- Authors
- He, B., Ebarasi, L., Zhao, Z., Guo, J., Ojala, J.R., Hultenby, K., De Val, S., Betsholtz, C., Tryggvason, K.
- ID
- ZDB-PUB-140524-3
- Date
- 2014
- Source
- Journal of the American Society of Nephrology : JASN 25(12): 2764-77 (Journal)
- Registered Authors
- Betsholtz, Christer, De Val, Sarah, Ebarasi, Lwaki, He, Bing, Tryggvason, Karlynn, Zhao, Zhe
- Keywords
- Combinatorial regulation, Lmx1b and FoxC, NPHS2 expression, podocyte, transgenic zebrafish
- MeSH Terms
-
- Humans
- Mice, Inbred C57BL
- Phenotype
- Animals, Genetically Modified
- Zebrafish Proteins/metabolism*
- Forkhead Transcription Factors/metabolism*
- Animals
- Gene Expression Regulation*
- LIM-Homeodomain Proteins/metabolism
- Transcription Factors/metabolism*
- Zebrafish
- Mutagenesis
- Podocytes/cytology
- Podocytes/metabolism*
- Promoter Regions, Genetic
- Transcription, Genetic
- Enhancer Elements, Genetic
- Amino Acid Motifs
- Binding Sites
- Membrane Proteins/metabolism*
- Intracellular Signaling Peptides and Proteins/metabolism*
- HEK293 Cells
- Microscopy, Confocal
- Mice
- PubMed
- 24854274 Full text @ J. Am. Soc. Nephrol.
Citation
He, B., Ebarasi, L., Zhao, Z., Guo, J., Ojala, J.R., Hultenby, K., De Val, S., Betsholtz, C., Tryggvason, K. (2014) Lmx1b and FoxC Combinatorially Regulate Podocin Expression in Podocytes. Journal of the American Society of Nephrology : JASN. 25(12):2764-77.
Abstract
Podocin is a key protein of the kidney podocyte slit diaphragm protein complex, an important part of the glomerular filtration barrier. Mutations in the human podocin gene NPHS2 cause familial or sporadic forms of renal disease owing to the disruption of filtration barrier integrity. The exclusive expression of NPHS2 in podocytes reflects its unique function and raises interesting questions about its transcriptional regulation. Here, we further define a 2.5-kb zebrafish nphs2 promoter fragment previously described and identify a 49-bp podocyte-specific transcriptional enhancer using Tol2-mediated G0 transgenesis in zebrafish. Within this enhancer, we identified a cis-acting element composed of two adjacent DNA-binding sites (FLAT-E and forkhead) bound by transcription factors Lmx1b and FoxC. In zebrafish, double knockdown of Lmx1b and FoxC orthologs using morpholino doses that caused no or minimal phenotypic changes upon individual knockdown completely disrupted podocyte development in 40% of injected embryos. Co-overexpression of the two genes potently induced endogenous nphs2 expression in zebrafish podocytes. We found that the NPHS2 promoter also contains a cis-acting Lmx1b-FoxC motif that binds LMX1B and FoxC2. Furthermore, a genome-wide search identified several genes that carry the Lmx1b-FoxC motif in their promoter regions. Among these candidates, motif-driven podocyte enhancer activity of CCNC and MEIS2 was functionally analyzed in vivo. Our results show that podocyte expression of some genes is combinatorially regulated by two transcription factors interacting synergistically with a common enhancer. This finding provides insights into transcriptional mechanisms required for normal and pathologic podocyte functions.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping