Intron 抑制斑馬魚 myf-5 基因表現的關鍵序列(2/2)
Date Issued
2005
Date
2005
Author(s)
蔡懷楨
DOI
932313B002026
Abstract
Myf-5 is a basic helix-loop-helix transcription factor that controls muscle
differentiation. During early embryogensis, myf-5 expression is transient, somiteand
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.
Subjects
myf-5
intron
regulatory cis-elements
somite
repression
Publisher
臺北市：國立臺灣大學分子與細胞生物學研究所
Type
report
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