Xue Z T, Larsen K, Jochimsen B U
Department of Molecular Biology and Plant Physiology, University of Aarhus, Denmark.
Plant Mol Biol. 1991 May;16(5):899-906. doi: 10.1007/BF00015081.
The effect of lowering oxygen concentration on the expression of nodulin genes in soybean callus tissue devoid of the microsymbiont has been examined. Poly(A)+ RNA was isolated from tissue cultivated in 4% oxygen and in normal atmosphere. Quantitative mRNA hybridization experiments using nodule-specific uricase (Nodulin-35) and sucrose synthase (Nodulin-100) cDNA probes confirmed that the synthesis of the uricase and sucrose synthase is controlled by oxygen at the mRNA level. The steady-state levels of uricase and sucrose synthase mRNA increased significantly (5-6- and 4-fold respectively) when the callus tissue was incubated at reduced oxygen concentration. Concomitant with the increase in mRNA level a 6-fold increase in specific activity of sucrose synthase was observed. Two messengers representing poly-ubiquitin precursors also responded to lowering the oxygen concentration. The increase was about 5-fold at 4% oxygen. No expression at atmospheric oxygen or in response to low oxygen was observed when using cDNA probes for other nodulin genes such as leghemoglobin c3, nodulin-22 and nodulin-44.
研究了降低氧浓度对不含微共生体的大豆愈伤组织中根瘤菌素基因表达的影响。从在4%氧气和正常大气环境中培养的组织中分离出聚腺苷酸加尾RNA（Poly(A)+ RNA）。使用根瘤特异性尿酸酶（根瘤菌素-35）和蔗糖合酶（根瘤菌素-100）cDNA探针进行的定量mRNA杂交实验证实，尿酸酶和蔗糖合酶的合成在mRNA水平受氧气控制。当愈伤组织在降低的氧浓度下培养时，尿酸酶和蔗糖合酶mRNA的稳态水平显著增加（分别增加5 - 6倍和4倍）。伴随着mRNA水平的增加，观察到蔗糖合酶的比活性增加了6倍。代表多聚泛素前体的两种信使也对降低氧浓度有反应。在4%氧气条件下增加约5倍。当使用针对其他根瘤菌素基因如豆血红蛋白c3、根瘤菌素-22和根瘤菌素-44的cDNA探针时，在大气氧浓度下未观察到表达，对低氧也无反应。
