Koshiba K, Kuroiwa A, Yamamoto H, Tamura K, Ide H
Biological Institute, Graduate School of Science, Tohoku University, Sendai, Japan.
J Exp Zool. 1998 Dec 15;282(6):703-14. doi: 10.1002/(sici)1097-010x(19981215)282:6<703::aid-jez6>3.0.co;2-p.
Msx genes, homeobox-containing genes, have been isolated as homologues of the Drosophila msh gene and are thought to play important roles in the development of chick or mouse limb buds. We isolated two Msx genes, Msx1 and Msx2, from regenerating blastemas of axolotl limbs and examined their expression patterns using Northern blot and whole mount in situ hybridization during regeneration and development. Northern blot analysis revealed that the expression level of both Msx genes increased during limb regeneration. The Msx2 expression level increased in the blastema at the early bud stage, and Msx1 expression level increased at the late bud stage. Whole mount in situ hybridization revealed that Msx2 was expressed in the distal mesenchyme and Msx1 in the entire mesenchyme of the blastema at the late bud stage. In the developing limb bud, Msx1 was expressed in the entire mesenchyme, while Msx2 was expressed in the distal and peripheral mesenchyme. The expression patterns of Msx genes in the blastemas and limb buds of the axolotl were different from those reported for chick or mouse limb buds. These expression patterns of axolotl Msx genes are discussed in relation to the blastema or limb bud morphology and their possible roles in limb patterning.
Msx基因，即含同源异型框的基因，已被分离出来，作为果蝇msh基因的同源物，并且被认为在鸡或小鼠肢体芽的发育中发挥重要作用。我们从蝾螈肢体再生芽基中分离出两个Msx基因，Msx1和Msx2，并在再生和发育过程中使用Northern印迹法和整体原位杂交技术检测了它们的表达模式。Northern印迹分析显示，在肢体再生过程中，两个Msx基因的表达水平均升高。Msx2的表达水平在芽早期的芽基中升高，而Msx1的表达水平在芽晚期升高。整体原位杂交显示，在芽晚期，Msx2在芽基的远端间充质中表达，而Msx1在芽基的整个间充质中表达。在发育中的肢体芽中，Msx1在整个间充质中表达，而Msx2在远端和周边间充质中表达。蝾螈芽基和肢体芽中Msx基因的表达模式与鸡或小鼠肢体芽中报道的表达模式不同。本文结合芽基或肢体芽的形态以及它们在肢体模式形成中的可能作用，对蝾螈Msx基因的这些表达模式进行了讨论。
