Yamane A, Mayo M L, Bringas P, Chen L, Huynh M, Thai K, Shum L, Slavkin H C
Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles, USA.
Dev Dyn. 1997 Aug;209(4):353-66. doi: 10.1002/(SICI)1097-0177(199708)209:4<353::AID-AJA3>3.0.CO;2-H.
The developing mouse tongue provides a model for discrete patterns of morphogenesis during short periods of embryonic development. Occipital somite-derived myogenic cells interact with cranial neural crest-derived ecto-mesenchymal cells to form the musculature of the tongue. The biochemical signals that control close range autocrine and/or paracrine signaling processes required to establish the fast-twitch complex tongue musculature are not known. The present study was designed to test the hypothesis that desmin, epidermal growth factor (EGF), and transforming growth factor-alpha (TGF alpha) and their cognate receptor, epidermal growth factor receptor (EGFr), are co-expressed during tongue myogenesis and define specific developmental stages of tongue muscle cell differentiation. To test this hypothesis, we performed studies to analyze the timing, position, and concentration of desmin, TGF alpha, EGF, and EGFr from embryonic day 9 (E9) through birth in Swiss Webster mouse tongue development. Desmin, TGF alpha, EGF, and EGFr co-localized to cells of myogenic lineage in the four occipital somites and subsequently in myoblasts and myotubes from E9 through E17. By newborn stage, desmin is localized to discrete regions in myofibers corresponding to Z-line delimiting sarcomeres, and A-band within sarcomeres; immunostaining for desmin, TGF alpha, and EGF persisted in differentiated myotubes and striated skeletal muscle. Desmin increased from 0.01% at E11 to 0.51% of the total protein by E17 and at birth. Concomitantly, the patterns and increases in TGF alpha, EGF, and EGFr showed significant increases during the same developmental period. The temporal and positional co-localization of TGF alpha, EGF, and EGFr support the hypothesis that autocrine and paracrine regulation of desmin by actions of growth factor ligand and receptor defines critical stages of tongue myogenesis.
发育中的小鼠舌头为胚胎发育短时期内形态发生的离散模式提供了一个模型。枕部体节衍生的生肌细胞与颅神经嵴衍生的外胚间充质细胞相互作用，形成舌头的肌肉组织。控制建立快速收缩复合舌肌组织所需的近距离自分泌和/或旁分泌信号传导过程的生化信号尚不清楚。本研究旨在检验以下假设：结蛋白、表皮生长因子（EGF）、转化生长因子-α（TGFα）及其同源受体表皮生长因子受体（EGFr）在舌肌生成过程中共同表达，并定义舌肌细胞分化的特定发育阶段。为了验证这一假设，我们进行了研究，分析了瑞士韦伯斯特小鼠舌头从胚胎第9天（E9）到出生期间结蛋白、TGFα、EGF和EGFr的时间、位置和浓度。结蛋白、TGFα、EGF和EGFr在四个枕部体节的生肌谱系细胞中共同定位，随后在从E9到E17的成肌细胞和肌管中共同定位。到新生阶段，结蛋白定位于肌纤维中与界定肌节的Z线以及肌节内的A带相对应的离散区域；结蛋白、TGFα和EGF的免疫染色在分化的肌管和横纹骨骼肌中持续存在。结蛋白从E11时占总蛋白的0.01%增加到E17时和出生时的0.51%。同时，TGFα、EGF和EGFr的模式和增加在同一发育时期显示出显著增加。TGFα、EGF和EGFr的时间和位置共同定位支持了以下假设：生长因子配体和受体的作用对结蛋白进行自分泌和旁分泌调节，定义了舌肌生成的关键阶段。
