SPECIFICATION OF MUSCLE PATTERN IN THE AMNIOTE LIMB

肌肉模式的规范和肌肉模式规范的骨骼和肌腱模式规范在发展中的四肢肌肉模式规范的关系的分子机制在很大程度上是未知的。 肌原性前体细胞迁移到肢体中，并最终分化成排列成45块解剖肌肉的慢肌纤维和快肌纤维。 [To描述何时何地肌原性细胞被模式化，克隆相关的肌原性细胞的命运将通过用CHAPOL复制缺陷型逆转录病毒文库标记肌原性前体来分析。lmx 1和hox转录因子似乎对于指定背腹、前-后和近端-远端肢体肌肉模式是关键的。 这些基因在肌肉形态发生的特定阶段中的作用将通过逆转录病毒在发育中的鸡肢中不适当的位置和不同时间错误表达lmx1和hoxd-11来评估。 鹌鹑-小鸡嵌合体和逆转录病毒，组织特异性基因表达的操作将决定最初在肢芽中胚层表达的lmx1和hoxd-11如何将其模式信息传递给肌肉，并提供了一种重要的手段来解剖肢体发育过程中肌肉，肌腱和骨骼形态发生之间的关系。 [In此外，通过筛选鸡肢文库中编码分泌蛋白的基因，正在寻找与肌肉形成有关的新基因]。

The molecular mechanisms underlying the specification of muscle pattern and the relationship of muscle pattern specification to skeletal and tendon pattern specification in the developing amniote limb are largely unknown. Myogenic precursor cells migrate into the limb and eventually differentiate into slow and fast myofibers arranged into 45 anatomical muscles. [To delineate when and where myogenic cells are being patterned, the fate of clonally-related myogenic cells will be analyzed by labeling myogenic precursors with CHAPOL replication defective retrovirus library.] lmx1 and hox transcription factors appear to be critical for specifying dorsal-ventral, anterior-posterior, and proximal-distal limb muscle pattern. The role of these genes in patterning particular phases of muscle morphogenesis will be assessed by retroviral misexpression of lmx1 and hoxd-11 in spatially inappropriate locations and at different times in the developing chick limb. Quail-chick chimeras and retroviral, tissue-specific manipulations of gene expression will determine how lmx1 and hoxd-11, initially expressed in the limb bud mesoderm, transmit their patterning information to muscle and provide an important means of dissecting the relationship between muscle, tendon, and skeleton morphogenesis during limb development. [In addition, novel genes involved in muscle patterning are being sought via a screen of a chick limb library for genes encoding secreted proteins].