MYOGENESIS SUBSEQUENT TO DENERVATION

在体内肌肉发生与发育和 神经系统的成熟。最近描述的技术允许 不干扰胎儿的小鼠胚胎实验操作 活力和成熟度。这些技术将应用于激光 切除幼龄胎儿脊髓，切断坐骨神经 对于年长的胎儿，允许评估去神经的影响 (在不同的发展时期)关于…的发展和成熟 哺乳动物的肌纤维。将用电子显微镜进行评估。 和形态测量学。我们还将评估胎儿去神经的效果。 不同肌球蛋白编码基因的表达研究 和肌动蛋白异构体的原位杂交研究 和免疫组织化学，使用免疫组织化学技术 这将允许区分存在于初级和初级的异构体 次级肌管。编码该基因的表达的时间进程 胎儿和成人形式的肌酸激酶及其编码基因 乙酰胆碱受体的各种亚单位(包括胎儿和成人 神经支配的后肢肌肉中的受体)将用原位测定 杂交。然后我们将评估去神经对 这些基因的表达和肌源性因子的编码基因 MyoD_1和Mygenin。拟议的研究将使我们能够评估 环境对肌肉发育过程中先天遗传程序的影响 1)它将允许评估细胞相互作用和神经元如何 可能在承诺、差异化或改变行为方面发挥作用 肌肉细胞。2)我将允许确定以下范围 神经调节是维持肌肉表型所必需的 发展的历程。根据建议的 研究将增加我们对细胞和分子的理解 肌肉发育的过程...“和”..。将是无价的 在设计和实施修复肌肉的技术时 由于遗传或环境原因造成的损坏或不起作用“。

In vivo myogenesis occurs simultaneously with the development and maturation of the nervous system. Recently described techniques permit experimental manipulation of mouse fetuses without interfering with fetal viability and maturation. These techniques will be applied to laser ablate the spinal cords of young fetuses and to cut the sciatic nerves of older fetuses, permitting the evaluation of the effects of denervation (at various developmental periods) on the development and maturation of mammalian myofibers. Evaluation will be made with electron microscopy and morphometry. We also will evaluate the effect of fetal denervation on the expression of muscle specific genes encoding the various myosin and actin isoforms in mouse hindlimb muscles with in situ hybridization and with immunohistochemistry, using an immunohistochemical technique which will permit differentiation of isoforms present in primary versus secondary myotubes. The time course of expression of genes encoding the fetal and adult forms of creatine kinase and the genes coding for the various subunits of the acetylcholine receptor (both the fetal and adult receptors) in innervated hindlimb muscles will be determined with in situ hybridization. We then will evaluate the effects of denervation on the expression of these genes and the genes encoding the myogenic factors MyoD1 and myogenin. The proposed studies will allow us to assess the effect of environment on the innate genetic program of developing muscle: 1) It will permit assessment of cell interactions and of how the neuron may play a role in commitment, differentiation, or change the behavior of muscle cells. 2) I will permit determination of the extent to which nerve regulation is required for the maintenance of muscle phenotypes in the course of development. Information generated from the proposed studies will increase our "...understanding of the cellular and molecular processes involved in muscle development ..." and "... will be invaluable in the design and implementation of techniques to repair muscles that are damaged or nonfunctional due to genetic or environmental causes".