ANALYSIS OF MOUSE EVX-GENES - EVX-1 DISPLAYS GRADED EXPRESSION IN THE PRIMITIVE STREAK
ANALYSIS OF MOUSE EVX-GENES - EVX-1 DISPLAYS GRADED EXPRESSION IN THE PRIMITIVE STREAK
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DOI：
10.1016/0012-1606(92)90232-6
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发表时间：
1992-05-01
影响因子：
2.7
通讯作者：
MARTIN, GR
中科院分区：
文献类型：
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作者：
DUSH, MK;MARTIN, GR
利用PCR技术分离出了两个小鼠基因Evx-1和Evx-2，它们各自编码一个与果蝇evenskipped基因同源结构域密切相关的同源结构域。这些基因的结构和序列进行了描述。定位研究将Evx-1定位于6号染色体，靠近Hox-1基因簇，Evx-2定位于2号染色体，靠近Hox-4基因簇。这些联系的演变影响进行了讨论。胚胎中Evx表达的RNA原位杂交分析表明，原肠胚形成期间Evx-1表达存在显着模式，而该技术在任何阶段都无法检测到Evx-2 RNA。Evx-1 RNA首次在原肠胚形成开始前不久在含有细胞的外胚层区域中检测到，这些细胞很快就会在原条中被发现。Evx-1的这种局部表达为原肠胚形成前小鼠胚胎外胚层的区域差异提供了第一个分子证据。在整个原肠胚形成过程中，Evx-1的表达仅限于条纹附近和条纹内的细胞，并且表达是分级的，RNA水平从后到前降低。基于命运映射研究表明，不同类型的中胚层出现从不同地区的原始条纹和我们的观察，高水平的表达定位于该地区，将产生胚外和腹侧中胚层，我们推测thatEvx-1中起着重要作用的中胚层细胞命运的背腹侧规格。
Two mouse genes,Evx-1andEvx-2, each encoding a homeodomain closely related to that of theDrosophila evenskippedgene were isolated using a PCR-based strategy. The structure and sequence of these genes are described. Mapping studies localizedEvx-1to chromosome 6, near theHox-1gene cluster, andEvx-2to chromosome 2, near theHox-4cluster. The evolutionary implications of these linkages are discussed. RNAin situhybridization analysis ofEvxexpression in embryos demonstrated a striking pattern ofEvx-1expression during gastrulation, whereasEvx-2RNA could not be detected at any stage by this technique.Evx-1RNA is first detected shortly before the onset of gastrulation in a region of ectoderm containing cells that will soon be found in the primitive streak. This localized expression ofEvx-1provides the first molecular evidence for regional differences in the mouse embryonic ectoderm before gastrulation. Throughout gastrulation,Evx-1expression is limited to cells near and within the streak and that expression is graded, with a posterior-to-anterior decrease in the level of RNA. Based on fate-mapping studies indicating that different types of mesoderm emerge from different regions of the primitive streak and our observation that high levels of expression are localized to the region that will give rise to extraembryonic and ventral mesoderm, we speculate thatEvx-1plays a role in the dorsoventral specification of mesodermal cell fate.