Schilder Rudolf J, Raynor Megan
Department of Entomology, Pennsylvania State University, 501 Ag Sciences & Industries Building, University Park, PA 16802, USA
Department of Biology, Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA.
J Exp Biol. 2017 Oct 1;220(Pt 19):3508-3518. doi: 10.1242/jeb.160523.
Studies of organismal and tissue biomechanics have clearly demonstrated that musculoskeletal design is strongly dependent on experienced loads, which can vary in the short term, as a result of growth during life history and during the evolution of animal body size. However, how animals actually perceive and make adjustments to their load-bearing musculoskeletal elements that accommodate variation in their body weight is poorly understood. We developed an experimental model system that can be used to start addressing these open questions, and uses hypergravity centrifugation to experimentally manipulate the loads experienced by We examined effects of this manipulation on leg muscle alternative splicing of the sarcomere gene troponin T (; Fbgn0004169, herein referred to by its synonym ), a process that was previously demonstrated to precisely correlate with quantitative variation in body weight in Lepidoptera and rat. In a similar fashion, hypergravity centrifugation caused fast (i.e. within 24 h) changes to fly leg muscle alternative splicing that correlated with body weight variation across eight lines. Hypergravity treatment also appeared to enhance leg muscle function, as centrifuged flies showed an increased negative geotaxis response and jump ability. Although the identity and location of the sensors and effectors involved remains unknown, our results provide further support for the existence of an evolutionarily conserved mechanism that translates signals that encode body weight into appropriate skeletal muscle molecular and functional responses.
对生物体和组织生物力学的研究清楚地表明，肌肉骨骼设计强烈依赖于所经历的负荷，由于生命史中的生长以及动物体型进化过程中的生长，这些负荷在短期内可能会有所不同。然而，动物如何实际感知并对其承重的肌肉骨骼元件进行调整以适应体重变化，目前还知之甚少。我们开发了一个实验模型系统，可用于开始解决这些悬而未决的问题，并利用超重力离心来实验性地操纵所经历的负荷。我们研究了这种操纵对腿部肌肉肌节基因肌钙蛋白T（；Fbgn0004169，此处用其同义词指代）可变剪接的影响，这一过程先前已被证明与鳞翅目昆虫和大鼠体重的定量变化精确相关。以类似的方式，超重力离心导致果蝇腿部肌肉可变剪接快速（即24小时内）变化，这与八条品系的体重变化相关。超重力处理似乎还增强了腿部肌肉功能，因为经离心处理的果蝇表现出更强的负趋地性反应和跳跃能力。尽管所涉及的传感器和效应器的身份和位置仍然未知，但我们的结果为存在一种进化上保守的机制提供了进一步支持，该机制将编码体重的信号转化为适当的骨骼肌分子和功能反应。
