Departmento de Biología Molecular de Plantas, Centro de Investigación sobre Fijación de Nitrógeno, U.N.A.M., Apartado Postal 565-A, Cuernavaca, Mor., México.
Plant Mol Biol. 1987 Jan;9(1):65-74. doi: 10.1007/BF00017988.
Glutamine synthetase expression was studied in developing root-nodules of common bean with regard to the time-course of specific activity, antigen accumulation, polypeptide composition and in vitro translation products. This analysis shows that the nodule-specific GS polypeptide (GS-gamma) is detected prior to the nitrogenase acetylene-reducing activity, and that its accumulation together with that of the GS-alpha and GS-beta polypeptides vary with nodule age. GS-gamma is present in ineffective nodules, although in a lower ratio to GS-beta than in wild-type nodules. Comparisons of in vitro translated and in vivo synthesized GS polypeptides suggest no post-translational modifications. The possible factors and mechanisms involved in the regulation of expression of GS polypeptides are discussed.
研究了普通豆科植物根瘤中谷氨酰胺合成酶（GS）的表达，包括比活、抗原积累、多肽组成和体外翻译产物的时程变化。该分析表明，在固氮酶乙炔还原活性之前即可检测到豆科植物根瘤特异的 GS 多肽（GS-γ），并且其积累与 GS-α和 GS-β多肽的积累随根瘤年龄而变化。GS-γ存在于无效根瘤中，尽管其与 GS-β的比值低于野生型根瘤。体外翻译和体内合成 GS 多肽的比较表明不存在翻译后修饰。讨论了调节 GS 多肽表达的可能因素和机制。
