School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.
Exp Cell Res. 2013 Apr 1;319(6):860-74. doi: 10.1016/j.yexcr.2013.01.002. Epub 2013 Jan 10.
The small heat shock protein HspB1 (Hsp27) is abundantly expressed in embryonic muscle tissues of a wide variety of vertebrate species. However, the functional significance of this expression pattern is not well established. In the present study, we observed specific, high level expression of HspB1 protein and an HspB1 gene reporter in developing craniofacial muscles of the zebrafish, Danio rerio, and examined the consequences of reducing HspB1 expression to the development and growth of these muscles. Quantitative morphometric analyses revealed a reduction in the cross-sectional area of myofibers in embryos expressing reduced HspB1 levels by as much as 47% compared to controls. In contrast, we detected no differences in the number of myofibrils or associated nuclei, nor the number, size or development of chondrocytes in surrounding tissues. We also did not detect changes to the overall organization of sarcomeres or myofibrils in embryos expressing reduced levels of HspB1. Together our results reveal a critical role for HspB1 in the growth of myofibrils and provide new insight into the mechanism underlying its developmental function.
小分子热休克蛋白 HspB1（Hsp27）在多种脊椎动物的胚胎肌肉组织中大量表达。然而，这种表达模式的功能意义尚未得到很好的确立。在本研究中，我们观察到斑马鱼 Danio rerio 颅面肌肉中 HspB1 蛋白和 HspB1 基因报告基因的特异性高表达，并研究了降低 HspB1 表达对这些肌肉发育和生长的影响。定量形态计量学分析显示，与对照组相比，表达水平降低的 HspB1 胚胎的肌纤维横截面积减少了多达 47%。相比之下，我们没有发现肌原纤维或相关核的数量、周围组织中软骨细胞的数量、大小或发育有任何差异。我们也没有检测到表达水平降低的 HspB1 胚胎中肌节或肌原纤维的整体组织发生变化。我们的研究结果揭示了 HspB1 在肌原纤维生长中的关键作用，并为其发育功能的机制提供了新的见解。
