Link G, Coen D M, Bogorad L
Cell. 1978 Nov;15(3):725-31. doi: 10.1016/0092-8674(78)90258-1.
Mesophyll cells and bundle sheath cells, the dimorphic photosynthetic cell types in the C4 plant Zea mays, differ in protein composition. In particular, the large subunit of the chloroplast enzyme ribulose-1,5-bisphosphate carbocylase (EC 4.1.1.39) is found entirely or almost exclusively in bundle sheath cells. The DNA sequence coding for this polypeptide is contained in the chloroplast DNA of both mesophyll cells and bundle sheath cells. RNA complementary to this coding sequence has been detected in RNA from bundle sheath cells, but is almost or entirely absent from mesophyll cells. Similarly, translatable mRNA for this polypeptide has been detected in RNA from bundle sheath cells, but not from mesophyll cells. Portions of the 4200 base pair maize plastid DNA sequence Bam 9 outside the large subunit gene region appear to be transcribed in mesophyll cells. Thus differential gene expression at the mRNA level has been directly demonstrated to occur in these two cell types.
叶肉细胞和维管束鞘细胞是C4植物玉米中两种不同形态的光合细胞类型，它们的蛋白质组成有所不同。特别是，叶绿体酶核酮糖-1,5-二磷酸羧化酶（EC 4.1.1.39）的大亚基完全或几乎只存在于维管束鞘细胞中。编码该多肽的DNA序列存在于叶肉细胞和维管束鞘细胞的叶绿体DNA中。与该编码序列互补的RNA已在维管束鞘细胞的RNA中检测到，但在叶肉细胞中几乎不存在或完全不存在。同样，该多肽的可翻译mRNA已在维管束鞘细胞的RNA中检测到，但在叶肉细胞中未检测到。大亚基基因区域外4200碱基对玉米质体DNA序列Bam 9的部分似乎在叶肉细胞中被转录。因此，已直接证明这两种细胞类型在mRNA水平上存在差异基因表达。
