Mercola M, Wang C Y, Kelly J, Brownlee C, Jackson-Grusby L, Stiles C, Bowen-Pope D
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts.
Dev Biol. 1990 Mar;138(1):114-22. doi: 10.1016/0012-1606(90)90181-h.
Murine homologs of the PDGF A, PDGF B, and PDGF receptor alpha subunit genes were cloned. These were used, together with a mouse PDGF receptor beta subunit cDNA clone, to monitor gene expression in early postimplantation mouse embryos and in F9 embryonal carcinoma cells. RNAse protection analysis shows that PDGF A chain, but not B chain, mRNA is expressed in 6.5- to 8.5-day embryonic and extraembryonic tissues. Both alpha and beta receptor subunit mRNAs are expressed in early embryos, however, alpha subunit mRNA appears earlier and is more abundant than beta subunit mRNA. Undifferentiated F9 embryonal carcinoma stem cells express abundant levels of A chain, but not B chain, mRNA. Neither of the PDGF receptor genes is expressed in stem cells. Treatment with retinoic acid stimulates expression of both PDGF receptor genes. As in postimplantation mouse embryos, alpha receptor subunit mRNA appears earlier and is substantially more abundant than beta subunit mRNA. Collectively, these data demonstrate that the genes encoding the two chains of PDGF and their receptors are regulated independently during development and suggest that the two systems have some nonoverlapping functions in vivo. PDGF A, but not PDGF B, may be particularly important in modulating early events in mouse embryonic development.
血小板衍生生长因子A、血小板衍生生长因子B以及血小板衍生生长因子受体α亚基基因的小鼠同源基因被克隆出来。这些基因与一个小鼠血小板衍生生长因子受体β亚基cDNA克隆一起，被用于监测植入后早期小鼠胚胎和F9胚胎癌细胞中的基因表达。核糖核酸酶保护分析表明，血小板衍生生长因子A链而非B链的mRNA在6.5至8.5天的胚胎及胚胎外组织中表达。α和β受体亚基的mRNA在早期胚胎中均有表达，然而，α亚基mRNA出现得更早且比β亚基mRNA更丰富。未分化的F9胚胎癌干细胞表达大量的A链mRNA，但不表达B链mRNA。血小板衍生生长因子受体基因在干细胞中均不表达。用视黄酸处理可刺激两种血小板衍生生长因子受体基因的表达。与植入后小鼠胚胎的情况一样，α受体亚基mRNA出现得更早且比β亚基mRNA丰富得多。总体而言，这些数据表明，编码血小板衍生生长因子两条链及其受体的基因在发育过程中受到独立调控，并表明这两个系统在体内具有一些不重叠的功能。血小板衍生生长因子A而非血小板衍生生长因子B在调节小鼠胚胎发育的早期事件中可能尤为重要。
