Amali Aseervatham Anusha, Lin Cliff Ji-Fan, Chen Yi-Hsuan, Wang Wei-Lun, Gong Hong-Yi, Lee Chiou-Yueh, Ko Yen-Lin, Lu Jenn-Khan, Her Guor Mour, Chen Thomas T, Wu Jen-Leih
Laboratory of Marine Molecular Biology and Biotechnology, Institute of Zoology, Academia Sinica, NanKang, Taipei, Taiwan.
Dev Dyn. 2004 Apr;229(4):847-56. doi: 10.1002/dvdy.10454.
Myostatin, a secreted growth and differentiation factor (GDF-8) belongs to transforming growth factor (TGF-beta) superfamily that plays as a negative regulator of skeletal muscle development and growth. Recently, myostatin has been isolated from fish; however, its role in muscle development and growth remains unknown. Here, we present the expression of myostatin during development and the effects of its knock-down on various genes such as muscle regulatory transcription factors (MRFs), muscle-specific proteins (MSP), and insulin-like growth factors (IGFs). The myostatin expression was found to be maternal as it starts in one-cell stage onward. The reverse transcription-polymerase chain reaction (RT-PCR), in situ hybridization, and Southern and Northern blots demonstrated that the myostatin expression is not only restricted to skeletal muscle, but it expressed all the tested tissues. Expression of myostatin was effected by using antisense morpholinos resulted in significant phenotypic difference in stages 18 and 20 hours postfertilization (hpf). To confirm the specificity of myostatin morpholino, furthermore, a rescue experiment was conducted. The length as well as width of somites was increased with almost no gap in between the somites. In addition, it deserves to mention that this is a first animal model that shows changes in the size of the somites. Moreover, analyses of MRFs, MSP, and IGFs in the knock-down embryos by RT-PCR revealed the up-regulation of MyoD, Myogenin, and Mck transcription, whereas IGF-2 transcription showed mild response with no effect on IGF-1, Desmin, and Myf5. In situ hybridization showed that there was an increase in the number of somites from 3 to 4 at 13 and 22 hpf. Taken together, these data suggest that myostatin plays a major role during myogenesis, apart from inhibition of proliferation as well as differentiation.
肌肉生长抑制素是一种分泌型生长分化因子(GDF - 8),属于转化生长因子(TGF - β)超家族,是骨骼肌发育和生长的负调节因子。最近,肌肉生长抑制素已从鱼类中分离出来;然而,其在肌肉发育和生长中的作用仍不清楚。在此,我们展示了肌肉生长抑制素在发育过程中的表达情况,以及其敲低对各种基因的影响,如肌肉调节转录因子(MRFs)、肌肉特异性蛋白(MSP)和胰岛素样生长因子(IGFs)。发现肌肉生长抑制素的表达是母源性的,因为它从单细胞阶段就开始了。逆转录聚合酶链反应(RT - PCR)、原位杂交以及Southern和Northern印迹表明,肌肉生长抑制素的表达不仅局限于骨骼肌,还在所有测试组织中表达。使用反义吗啉代寡核苷酸影响肌肉生长抑制素的表达,导致受精后18和20小时(hpf)阶段出现显著的表型差异。此外,为了证实肌肉生长抑制素吗啉代寡核苷酸的特异性,进行了拯救实验。体节的长度和宽度都增加了,体节之间几乎没有间隙。此外,值得一提的是,这是第一个显示体节大小变化的动物模型。此外,通过RT - PCR对敲低胚胎中的MRFs、MSP和IGFs进行分析,发现MyoD、Myogenin和Mck转录上调,而IGF - 2转录显示出轻微反应,对IGF - 1、结蛋白和Myf5没有影响。原位杂交显示,在13和22 hpf时,体节数量从3个增加到了4个。综上所述,这些数据表明,肌肉生长抑制素除了抑制增殖和分化外,在肌生成过程中也起着重要作用。