Duprez D, Lapointe F, Edom-Vovard F, Kostakopoulou K, Robson L
Institut d'Embryologie Cellulaire et Moleculaire du CNRS (UPR 9024) et du College de France, 49 bis avenue de la Belle Gabrielle, 94736, Nogent Sur Marne Cedex, France.
Mech Dev. 1999 Apr;82(1-2):151-63. doi: 10.1016/s0925-4773(99)00040-4.
Development of the musculature in chick limbs involves tissue and cellular patterning. Patterning at the tissue level leads to the precise arrangement of specific muscles; at the cellular level patterning gives rise to the fibre type diversity in muscles. Although the data suggests that the information controlling muscle patterning is localised within the limb mesenchyme and not in the somitic myogenic precursor cells themselves, the mechanisms underlying muscle organisation have still to be elucidated. The anterior-posterior axis of the limb is specified by a group of cells in the posterior region of the limb mesenchyme, called the zone of polarizing activity (ZPA). When polarizing-region cells are grafted to the anterior margin of the bud, they cause mirror-image digit duplications to be produced. The effect of ZPA grafts can be reproduced by application of retinoic acid (RA) beads and by grafting sonic hedgehog (SHH)-expressing cells to the anterior margin of the limb. Although most previous studies have looked at changes of the skeletal patterning, ZPA and RA also affect muscle patterning. In this report, we investigated the role of SHH in tissue and cellular patterning of forearm wing muscles. Ectopic application of a localised source of SHH to the anterior margin of the wing, leading to complete digit duplication, is able to transform anterior forearm muscles into muscles with a posterior identity. Moreover, the ectopic source of SHH induces a mirror image duplication of the normal posterior muscles fibre types in the new posterior muscles. The reorganisation of the slow fibres can be detected before muscle mass cleavage has started; suggesting that the appropriate fibre type arrangement is in place before the splitting process can be observed.
鸡胚肢体肌肉组织的发育涉及组织和细胞的模式形成。组织水平的模式形成导致特定肌肉的精确排列；细胞水平的模式形成则产生肌肉中纤维类型的多样性。尽管数据表明控制肌肉模式形成的信息定位于肢体间充质内，而非体节生肌前体细胞本身，但肌肉组织的潜在机制仍有待阐明。肢体的前后轴由肢体间充质后部区域的一组细胞确定，该区域称为极化活性区（ZPA）。当将极化区域的细胞移植到芽的前缘时，会导致镜像数字重复产生。ZPA移植的效果可以通过应用视黄酸（RA）珠以及将表达音猬因子（SHH）的细胞移植到肢体前缘来重现。尽管大多数先前的研究关注骨骼模式的变化，但ZPA和RA也会影响肌肉模式。在本报告中，我们研究了SHH在前臂翼肌组织和细胞模式形成中的作用。将局部来源的SHH异位应用于翅膀前缘，导致完全的数字重复，能够将前臂前部肌肉转化为具有后部特征的肌肉。此外，SHH的异位来源在新的后部肌肉中诱导了正常后部肌肉纤维类型的镜像重复。在肌肉质量分裂开始之前就能检测到慢纤维的重组；这表明在观察到分裂过程之前，适当的纤维类型排列就已到位。
