ZFIN ID: ZDB-PUB-040719-8
Novel cis-element in intron 1 represses somite expression of zebrafish myf-5
Lin, C.Y., Chen, Y.H., Lee, H.C., and Tsai, H.J.
Date: 2004
Source: Gene   334: 63-72 (Journal)
Registered Authors: Chen, Yau-Hung, Tsai, Huai-Jen
Keywords: Myf-5, Intron, Somite, Regulatory cis-elements, Repression
MeSH Terms:
  • Animals
  • Embryo, Nonmammalian/metabolism
  • Embryonic Development
  • Enhancer Elements, Genetic*
  • Gene Expression Regulation, Developmental
  • Green Fluorescent Proteins
  • In Situ Hybridization
  • Introns/genetics*
  • Luminescent Proteins/genetics
  • Luminescent Proteins/metabolism
  • Microinjections
  • Microscopy, Fluorescence
  • Plasmids/administration & dosage
  • Plasmids/genetics
  • Recombinant Fusion Proteins/genetics
  • Recombinant Fusion Proteins/metabolism
  • Somites/metabolism*
  • Zebrafish/embryology
  • Zebrafish/genetics*
  • Zebrafish Proteins/genetics*
  • Zebrafish Proteins/metabolism
PubMed: 15256256 Full text @ Gene
Myf-5 is a basic helix-loop-helix (bHLH) transcription factor that controls muscle differentiation. During early embryogenesis, myf-5 expression is transient, somite- and stage-specific. However, the negative regulation of myf-5 is poorly understood. We constructed a plasmid [(-9977/-1)/E1/I1/E2/GFP] that contains the sequence -9977 to -1, exon 1 (E1), intron 1 (I1), and exon 2 (E2) of zebrafish (Danio rerio) myf-5 and a reporter GFP gene. This plasmid was microinjected into zebrafish zygotes. Surprisingly, the somite-specific expression rate of reporter GFP in the transgenic embryos was extremely low (2%, n=392), compared to that of (-9977/-1)/GFP (92%, n=210). Dramatic repression of myf-5 expression was also observed in embryos microinjected with plasmids in which the sequence -8600/-1, -2937/-1 or -290/-1 was linked to E1/I1/E2/GFP. Thus, intron 1 contains a silencer that specifically represses the activity of myf-5. Functional analysis of intron 1 showed a strong, negative, cis-regulatory element was located at +502/+835. Its function was orientation- and position-dependent. The repressive capability of this silencer was completely dependent on two core motifs, IE1 (+502/+527) and IE2 (+816/+835), and a 156-bp spanning sequence that lies between them. This is the first study to identify a novel, cis-acting silencer in intron 1 that is crucial to negatively regulating zebrafish myf-5 expression.