Su M W, Suzuki H R, Solursh M, Ramirez F
Brookdale Center for Molecular Biology, Mt. Sinai School of Medicine, New York, NY 10029.
Development. 1991 Apr;111(4):1179-87. doi: 10.1242/dev.111.4.1179.
We have isolated cDNAs encoding a novel Xenopus homeodomain-containing protein homologous to the mouse Hox-7.1 and the Drosophila muscle segment homebox (msh). Northern blot and RNAase protection experiments established that transcripts of the frog gene, termed Xhox-7.1, first appear at about the beginning of gastrulation. After a rapid increase, mRNA levels plateau between the neurula and middle-tailbud stages, and decrease steadily thereafter. In situ hybridization localized the Xhox-7.1 message to the dorsal mesodermal mantle of gastrula stage embryos. Comparison of the hybridization patterns of progressively more anterior cross-section of tailbud stage embryos localized the signal to the dorsal neural tube and neural crest, to specific regions of the lateral plate mesoderm, and to the cardiogenic region. By the tadpole stage, the Xhox-7.1 message appears only at specific sites in the central nervous system, such as in the dorsal hindbrain. Thus, during embryonic development levels of Xhox-7.1 expression decrease as the transcript becomes more progressively localized. Finally, evidence is presented of a distinct msh-like transcript (provisionally termed Xhox-7.1') which begins to accumulate at early-gastrula stage, as well.
我们已经分离出了编码一种新型非洲爪蟾含同源异型结构域蛋白的cDNA，该蛋白与小鼠Hox-7.1和果蝇肌肉节段同源框（msh）同源。Northern印迹和RNA酶保护实验表明，这种被称为Xhox-7.1的青蛙基因转录本大约在原肠胚形成开始时首次出现。在快速增加之后，mRNA水平在神经胚和中尾芽阶段之间达到稳定状态，此后稳步下降。原位杂交将Xhox-7.1信息定位到原肠胚阶段胚胎的背侧中胚层套膜。对尾芽阶段胚胎逐渐更靠前的横截面杂交模式的比较将信号定位到背侧神经管和神经嵴、侧板中胚层的特定区域以及心脏发生区域。到蝌蚪阶段，Xhox-7.1信息仅出现在中枢神经系统的特定部位，如背侧后脑。因此，在胚胎发育过程中，随着转录本定位越来越局限，Xhox-7.1的表达水平下降。最后，有证据表明存在一种独特的类似msh的转录本（暂称为Xhox-7.1'），它也在原肠胚早期开始积累。
