Comparative role of phosphotyrosine kinase domains of c-ros and c-ret protooncogenes in metanephric development with respect to growth factors and matrix morphogens
Comparative role of phosphotyrosine kinase domains of c-ros and c-ret protooncogenes in metanephric development with respect to growth factors and matrix morphogens
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DOI：
10.1006/dbio.1996.0204
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发表时间：
1996-08-25
影响因子：
2.7
通讯作者：
Kanwar, YS
中科院分区：
文献类型：
--
作者：
Liu, ZZ;Wada, J;Kanwar, YS
具有酪氨酸激酶催化结构域的受体样原癌基因在肿瘤和胎儿组织中表达，并可能在胚胎发育中发挥作用。哪一种原癌基因可能在胚胎肾发育的“后诱导”时期起主导作用，即，第10天以后，在本研究中通过使用体外器官培养系统进行了处理。各种受体样原癌基因的作用，重点是c-ros和c-rer，研究了反义寡核苷酸（ODN）基因靶向策略在后肾发育的一个点时，上皮和间充质之间的相互诱导的相互作用已经启动，并猖獗。此外，他们与其他形态，如细胞外基质（ECM）蛋白和生长因子的关系，进行了研究。初步原位杂交和RT-PCR分析显示，在胚胎肾脏c-ros和c-ret的时空表达相似。在第13天，它们主要表达在生肾区和输尿管芽分支的发育中的肾单位中，其中来自间充质配体的信号被转导至上皮细胞表面受体。在新生儿肾脏中观察到最小表达。包括反义ODN，来自磷酸酪氨酸激酶结构域，抑制后肾生长的器官培养中，观察到最显着的效果与c-ret反义ODN。c-ret诱导的畸形发生效应的特征在于肾单位的数量减少，间充质细胞萎缩，输尿管芽枝尖端的尖锐度丧失。有趣的是，输尿管芽枝在萎缩的间质中继续生长。c-ros和c-ret反义ODN都减少了各种ECM蛋白的基因表达和生物合成。蛋白多糖，在上皮：间充质界面表达，受到最不利的影响，特别是通过c-ret反义。用c-ret处理后肾外植体不影响c-ros的基因表达，反之亦然。c-ret反义作用的特异性也通过抗Ret蛋白免疫反应性的降低来反映。这些研究扩展到建立c-ret原癌基因和一些生长因子之间的关系，这些生长因子已知通过位于输尿管芽支的酪氨酸激酶样受体影响肾脏发育，该部位显然也表达c-ret。在检查的各种生长因子中，转化生长因子-α（TGF-α）和胰岛素样生长因子-I（IGF-I）对后肾外植体具有最显著的营养作用，并引起Ret蛋白的最大磷酸化。此外，TGF-α或IGF-I和c-ret反义ODN外植体的同时暴露导致c-ret诱导的后肾畸形效应部分恢复。这些数据表明，虽然一些原癌基因共享类似的催化结构域，c-ret发挥了重要作用，在“后诱导"时期的后肾发育的干扰生长因子依赖的ECM形态发生大分子的表达，特别是蛋白多糖，也影响某些尚未确定的生长因子介导的磷酸化机制（S）涉及c-ret。(C)出版社：Academic Press，Inc.
Receptor-like protooncogenes, with tyrosine kinase catalytic domains, are expressed in neoplastic and fetal tissues and potentially have a role in embryonic development. Which protooncogene may have the dominant role in embryonic renal development during the ''postinductive'' period, i.e., Day 10 onward, was addressed in this study by utilizing an in vitro organ culture system. The role of various receptor-like protooncogenes, with the emphasis on c-ros and c-rer, was investigated by antisense-oligodeoxynucleotide (ODN) gene-targeting strategies at a point in metanephric development when reciprocal-inductive interactions between the epithelium and mesenchyme have already been initiated and are rampant. Also, their relationship with other morphogens, like extracellular matrix (ECM) proteins and growth factors, was studied. Initial in situ hybridization and RT-PCR analyses revealed a similar spatiotemporal expression for both c-ros and c-ret in the embryonic kidneys. At Day 13, they were mainly expressed in the developing nephrons in the nephrogenic zone and ureteric bud branches, where the signals from the mesenchymal ligands are transduced to the epithelial cell surface receptors. Minimal expression was observed in the newborn kidneys. Inclusion of antisense ODNs, derived from the phosphotyrosine kinase domains, inhibited metanephric growth in the organ culture; the most dramatic effects were observed with the c-ret antisense ODN. The c-ret-induced dysmorphogenetic effects were characterized as a decrease in the population of nephrons, atrophy of the mesenchymal cells, and loss of acuteness of the tips of ureteric bud branches. Interestingly, the ureteric bud branches continue to grow in the atrophic mesenchyme. Both c-ros and c-ret antisense ODNs reduced the gene expression and biosynthesis of various ECM proteins. The proteoglycans, expressed at the epithelial:mesenchymal interface, were most adversely affected, especially by the c-ret antisense. The treatment of metanephric explants with c-ret did not affect the gene expression of c-ros and vice versa. The specificity of the effects of c-ret antisense was also reflected by a decrease of anti-Ret protein immunoreactivity. The studies were extended to establish a relationship between c-ret protooncogene and some of a the growth factors which are known to influence renal development via their tyrosine kinase-like receptors localized in the ureteric bud branches, the site apparently where c-ret is also expressed. Among the various growth factors examined, transforming growth factor-alpha (TGF-alpha) and insulin like growth factor-I (IGF-I) had the most notable trophic effects on metanephric explants and caused maximal phosphorylation of Ret protein. In addition, concurrent exposure of TGF-alpha or IGF-I and c-ret antisense ODN explants caused partial recovery from the c-ret-induced dysmorphogenetic effects in the metanephroi. The data suggest that, although a number of protooncogenes share similar catalytic domains, c-ret plays a major role during a the ''postinductive'' period of metanephric development by perturbing the growth factor-dependent expression of ECM morphogenetic macromolecules, notably that of the proteoglycans, and also by affecting certain yet undefined growth factor-mediated phosphorylation mechanism(s) involving c-ret. (C) 1996 Academic Press, Inc.