Developmental transition of touch response from slow muscle-mediated coilings to fast muscle-mediated burst swimming in zebrafish
Developmental transition of touch response from slow muscle-mediated coilings to fast muscle-mediated burst swimming in zebrafish
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DOI：
10.1016/j.ydbio.2011.04.027
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发表时间：
2011-07-15
影响因子：
2.7
通讯作者：
Hirata, Hiromi
中科院分区：
文献类型：
--
作者：
Naganawa, Yuriko;Hirata, Hiromi
众所周知，在成年动物的行为中，慢肌和快肌分别用于长时间持续运动和短时间爆发性活动。然而，在早期动物运动中，慢肌和快肌的作用还没有得到彻底的研究。在野生型斑马鱼胚胎中，触觉刺激在受精后24小时（hpf）诱导由躯干和尾部的1-3次交替收缩组成的cobligation，并在48 hpf诱导爆发性游泳。但是，在不能飞的I同源物（flii）中有缺陷的胚胎，它编码一种肌动蛋白调节蛋白，在24 hpf时表现出正常的coherency，然后在48 hpf时表现出明显较慢的爆发性游泳。有趣的是，肌动蛋白纤维在突变快肌中紊乱，但在突变慢肌中却没有，这表明在48 hpf下游泳速度较慢是由于快肌组织缺陷造成的。事实上，通过消除仅在快肌中的Ca（2+）释放来扰乱快肌收缩，导致在24 hpf时的正常收缩和在48 hpf时的较慢爆发游泳，就像流感突变体所表现的那样。相反，通过敲低慢肌肌球蛋白基因使慢肌特异性失活，导致在24 hpf时完全丧失cobalt，尽管在48 hpf时保留了正常的爆发性游泳。这些发现表明，在24 hpf的cobalt介导的慢肌，而爆发游泳在48 hpf主要是由快肌执行。这与快肌分化跟随慢肌分化的事实相一致。这是第一次直接证明，慢肌和快肌在不同阶段的早期运动发育中具有不同的生理相关贡献。(C)2011 Elsevier Inc. All rights reserved.
It is well known that slow and fast muscles are used for long-term sustained movement and short bursts of activity, respectively, in adult animal behaviors. However, the contribution of the slow and fast muscles in early animal movement has not been thoroughly explored. In wild-type zebrafish embryos, tactile stimulation induces coilings consisting of 1-3 alternating contractions of the trunk and tail at 24 hours postfertilization (hpf) and burst swimming at 48 hpf. But, embryos defective in flightless I homolog (flii), which encodes for an actin-regulating protein, exhibit normal coilings at 24 hpf that is followed by significantly slower burst swimming at 48 hpf. Interestingly, actin fibers are disorganized in mutant fast muscle but not in mutant slow muscle, suggesting that slower swimming at 48 hpf is attributable to defects of the fast muscle tissue. In fact, perturbation of the fast muscle contractions by eliminating Ca(2+) release only in fast muscle resulted in normal coilings at 24 hpf and slower burst swimming at 48 hpf, just as flu mutants exhibited. In contrast, specific inactivation of slow muscle by knockdown of the slow muscle myosin genes led to complete loss of coilings at 24 hpf, although normal burst swimming was retained by 48 hpf. These findings indicate that coilings at 24 hpf is mediated by slow muscle only, whereas burst swimming at 48 hpf is executed primarily by fast muscle. It is consistent with the fact that differentiation of fast muscle follows that of slow muscle. This is the first direct demonstration that slow and fast muscles have distinct physiologically relevant contribution in early motor development at different stages. (C) 2011 Elsevier Inc. All rights reserved.