The physiological role of CTGF/CCN2 in zebrafish notochond development and biological analysis of the proximal promoter region.
During mouse embryogenesis, CTGF/CCN2 is expressed in zones containing hypertrophic chondroctyes and calcifying cartilage such as long bones, ribs, vertebral column, and phalanges. But in fish, its expression is yet unclear. Development of the vertebrae is morphologically similar among vertebrates, indicating that the underlying mechanism regulating the process is highly conserved during evolution. Analysis of 3.2kb of the CTGF/CCN2 proximal promoter sequence revealed a consensus TATAA box, putative AP1, Brn-2, CdxA, C/EBP alpha, C/EBP beta, C-Ets-, delta E, HFH-2, and HSF2 binding sites. Transient expression experiments with a 5'-deletion revealed at least 4 regulatory regions in the zebrafish CTGF/CCN2 gene, 2 with a stimulatory effect on transcription and 2 with an apparent inhibitory effect after IGF-I treatment in the ZFL cell line. To study the promoter-specific expression, we constructed a series of CTGF/CCN2 (3.0-, 2.5-, 2.0-, 1.5-, 1.0-, and 0.4-kb) promoter-driven green fluorescent protein (GFP) fragments encoding the GFP cDNA transgene which was microinjected into zebrafish embryos. Morphological studies of transgenic zebrafish indicated that the CTGF/CCN2 promoter-driven GFP transcripts appeared in the notochord. Targeted knockdown of the CTGF/CCN2 gene by two antisense morpholino oligonucleotides resulted in disruptions to notochord development. From a comparative point of view, this study of the CTGF/CCN2 gene in zebrafish may correlate well with those previously published on the mouse. These molecular results suggest that CTGF/CCN2 plays an important role in notochord development and is required for general embryonic development.
Chiou
Ming-Jyun
MJ
Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Jiaushi, Ilan 262, Taiwan, ROC.
Chao
Tsung-Tai
TT
Wu
Jen-Leih
JL
Kuo
Ching-Ming
CM
Chen
Jyh-Yih
JY
D000818:Animals; D055513:Connective Tissue Growth Factor; D018076:DNA, Complementary / Q000378:metabolism; D005091:Exons; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D017874:Immediate-Early Proteins / Q000096:biosynthesis / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis / Q000502:physiology*; D051379:Mice; D009672:Notochord / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism; D019076:Transgenes; D015027:Zebrafish
C526317:CCN2 protein, human; C526318:CCN2 protein, mouse; D018076:DNA, Complementary; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D014157:Transcription Factors; D055513:Connective Tissue Growth Factor; D049452:Green Fluorescent Proteins