Widespread expression of MyoD genes in Xenopus embryos is amplified in presumptive muscle as a delayed response to mesoderm induction.
Widespread expression of MyoD genes in Xenopus embryos is amplified in presumptive muscle as a delayed response to mesoderm induction.
复制标题
作为对中胚层诱导的延迟反应，非洲爪蟾胚胎中 MyoD 基因的广泛表达在推定肌肉中被放大。
DOI：
10.1073/pnas.88.20.9198
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发表时间：
1991
影响因子：
11.1
通讯作者：
Harvey,RP
中科院分区：
文献类型：
--
作者：
Harvey,RP
MyoD基因编码骨骼肌发生的一个重要调节因子。为了探究爪蟾胚胎中胚层诱导与MyoD表达之间的关系，我通过RNase保护检测了正常胚胎和培养的外植体MyoD mRNA水平。来自两个爪蟾MyoD基因拷贝的转录在中囊胚过渡时在整个胚胎中被微弱激活，并且这种激活发生在没有中胚层诱导的情况下。作为对诱导的响应，这种基础表达扩增50- 100倍，但在动物极外植体中，诱导mrna出现需要6-10小时，并且这种诱导需要事先合成蛋白质。当诱导“能力”丧失时，混杂转录本就会从动物外植体中消失，这表明这些事件之间存在联系。这些数据强调了MyoD在胚胎中的广泛但短暂的表达许可，仅在诱导下在假定的肌肉中繁殖和扩增。此外，肌肉特异性MyoD表达在中胚层诱导级联中相对较晚（原肠胚形成后）发生。
The MyoD gene codes for an important regulatory factor in skeletal myogenesis. To explore the relationship between mesoderm induction in Xenopus embryos and expression of MyoD, I have monitored MyoD mRNA levels in normal embryos and cultured explants by RNase protection. Transcription from the two Xenopus MyoD gene copies is activated weakly across the whole embryo at the midblastula transition, and this activation occurs in the absence of mesoderm induction. In response to induction this basal expression is amplified 50- to 100-fold, but in animal-pole explants 6-10 hr elapse before induced mRNAs appear, and this induction requires prior protein synthesis. The promiscuous transcripts disappear from animal explants at a time when induction "competence" is lost, suggesting a link between these events. The data highlight a broad, but transient, permissiveness for MyoD expression in embryos, which is propagated and amplified only in presumptive muscle in response to induction. Moreover, muscle-specific MyoD expression is a relatively late (postgastrulation) event in the mesoderm-induction cascade.