Sawbridge T I, Knight M R, Jenkins G I
Division of Biochemistry and Molecular Biology, University of Glasgow, UK.
Planta. 1996;198(1):31-8. doi: 10.1007/BF00197583.
The rbcS1, 2 and 3 genes of Phaseolus vulgaris are identical in coding sequence and we have studied their expression using gene-specific probes derived from their 3' non-coding regions. The genes differ in their relative levels of expression but show only minor qualitative differences in their regulation. Transcripts of the three genes are undetectable in primary leaves in the imbibed seed, accumulate early in leaf expansion reaching a maximum 7-10 d after sowing and decrease to low levels by the time expansion is complete. Both dark-grown and light-grown primary leaves exhibit this ontogenetic pattern of expression, although the light-grown leaves have two to three times more rbcS transcripts. Light can over-ride the ontogenetic control of rbcS expression; for example, when 7-d-old dark-grown primary leaves are illuminated there is a 6- to 12-fold increase in the transcript levels of the rbcS genes. Transfer of illuminated leaves to darkness results in the loss of transcripts of all three genes, but rbcS2 transcripts persist in the dark-adapted leaves. Possible physiological mechanisms of the ontogenetic regulation of expression are discussed.
菜豆的rbcS1、2和3基因在编码序列上是相同的，我们使用从其3'非编码区衍生的基因特异性探针研究了它们的表达。这些基因在相对表达水平上有所不同，但在调控方面仅表现出微小的质的差异。这三个基因的转录本在吸胀种子的初生叶中无法检测到，在叶片扩展早期积累，在播种后7 - 10天达到最大值，到扩展完成时降至低水平。无论是黑暗生长还是光照生长的初生叶都表现出这种个体发育的表达模式，尽管光照生长的叶片中rbcS转录本多两到三倍。光可以超越rbcS表达的个体发育控制；例如，当7天大的黑暗生长的初生叶受到光照时，rbcS基因的转录本水平会增加6到12倍。将光照的叶片转移到黑暗中会导致所有三个基因的转录本丢失，但rbcS2转录本在适应黑暗的叶片中持续存在。文中讨论了表达个体发育调控的可能生理机制。
