ID OF GENES DIFFERENTIALLY EXPRESSED IN DEVELOPING EMBRYONIC LIMB BUDS

建立基因所需基因的阐明和表征 形态发生过程中的纹样形成及其调控研究 是脊椎动物生物学许多方面的核心问题。它 可以预期，包括对营养刺激的反应在内的过程， 细胞间的相互作用、迁移、差异细胞增殖、 程序性细胞死亡等都参与其中。其中许多相同的过程 在肿瘤形成过程中以一种病理的方式重现。雏鸡肢体 发展是研究分子基础的一个有吸引力的系统。 形态发生过程中的图案形成。级别的关键事件 参与图案形成的组织/细胞相互作用一直很好 以这种有机体为特征的，调节模式形成的事件 似乎总体上与哺乳动物系统中的非常相似，而这 该系统易于进行生化和分子分析以及 涉及显微外科操作的研究。 这项长期计划的目标是分离出调节 鸡胚胎肢芽的形态发生。两种一般类型的方法 正在开发以实现这一目标：1)产生减法 丰富潜在调控和诱导基因的cDNA文库；以及2) 保守基因家族相关/新成员的鉴定 与其他发育调控过程有牵连 系统。目前，同源异型盒基因家族的两个新成员已经 鉴定了哪些基因在早期有选择地在肢芽中表达 发展。这些基因中的一个以分级的方式沿着 肢体的A-P轴，翼部比腿部丰富4到5倍 花蕾，暗示可能在花纹形成和/或 肢体类型同一性的确定。第二个基因似乎是 在后来的肢芽发育中选择性表达，并可能发挥作用 在后来的形态发生事件中，如重塑。

The elucidation and characterization of genes necessary for establishing pattern formation during morphogenesis and the study of their regulation are problems which are central to many aspects of vertebrate biology. It may be expected that processes including responses to trophic stimuli, cell-cell interactions, migration, differential cell multiplication, programmed cell death, etc. are all involved. Many of these same processes are recapitulated in a pathologic manner during oncogenesis. Chick limb development is an attractive system for studying the molecular basis for pattern formation during morphogenesis. Critical events at the level of tissue/cellular interactions involved in pattern formation have been well characterized in this organism, the events regulating pattern formation appear to be overall very similar to those in mammalian systems, and this system is readily amenable to biochemical and molecular analysis as well as studies involving microsurgical manipulation. It is the aim of this long-term project to isolate genes that regulate morphogenesis in the chick embryo limb bud. Two general types of approaches are being developed to achieve this aim: 1) the generation of subtracted cDNA libraries enriched for potential regulatory and induced genes; and 2) the identification of related/new members of conserved gene families that have been implicated in developmental regulatory processes in other systems. Currently, two new members of the homeobox gene family have been identified which are selectively expressed in limb buds during early development. One of these genes is expressed in a graded fashion along the A-P axis of the limb and is 4 to 5 fold more abundant in wing than leg buds, suggesting possible roles in pattern formation and/or the determination of limb-type identity. The second gene appears to be selectively expressed later in developing limb buds and might play a role in later morphogenetic events such as remodeling.