Identification and characterization of alternative promoters of zebrafish Rtn-4/Nogo genes in cultured cells and zebrafish embryos.
In mammals, the Nogo family consists of Nogo-A, Nogo-B and Nogo-C. However, there are three Rtn-4/Nogo-related transcripts were identified in zebrafish. In addition to the common C-terminal region, the N-terminal regions of Rtn4-n/Nogo-C1, Rtn4-m/Nogo-C2 and Rtn4-l/Nogo-B, respectively, contain 9, 25 and 132 amino acid residues. In this study, we isolated the 5'-upstream region of each gene from a BAC clone and demonstrated that the putative promoter regions, P1-P3, are functional in cultured cells and zebrafish embryos. A transgenic zebrafish Tg(Nogo-B:GFP) line was generated using P1 promoter region to drive green fluorescent protein (GFP) expression through Tol2-mediated transgenesis. This line recapitulates the endogenous expression pattern of Rtn4-l/Nogo-B mRNA in the brain, brachial arches, eyes, muscle, liver and intestines. In contrast, GFP expressions by P2 and P3 promoters were localized to skeletal muscles of zebrafish embryos. Several GATA and E-box motifs are found in these promoter regions. Using morpholino knockdown experiments, GATA4 and GATA6 were involved in the control of P1 promoter activity in the liver and intestine, while Myf5 and MyoD for the control of P1 and P3 promoter activities in muscles. These data demonstrate that zebrafish Rtn4/Nogo transcripts might be generated by coupling mechanisms of alternative first exons and alternative promoter usage.
Chen
Yi-Chung
YC
Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
Wu
Bo-Kai
BK
Chu
Cheng-Ying
CY
Cheng
Chia-Hsiung
CH
Han
Hau-Wei
HW
Chen
Gen-Der
GD
Lee
Ming-Ting
MT
Hwang
Pung-Pung
PP
Kawakami
Koichi
K
Chang
Chun-Che
CC
Huang
Chang-Jen
CJ
D017398:Alternative Splicing; D000818:Animals; D030801:Animals, Genetically Modified; D002460:Cell Line; D004625:Embryo, Nonmammalian / Q000378:metabolism; D050980:GATA Transcription Factors / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D051379:Mice; D009185:Myelin Proteins / Q000235:genetics* / Q000378:metabolism; D000070798:Nogo Proteins; D011401:Promoter Regions, Genetic; D029867:Xenopus Proteins / Q000235:genetics* / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins
D050980:GATA Transcription Factors; D009185:Myelin Proteins; D000070798:Nogo Proteins; C000603201:Rtn4 protein, mouse; C000592544:Rtn4a protein, zebrafish; D029867:Xenopus Proteins; D029961:Zebrafish Proteins