Sheen J Y, Bogorad L
Proc Natl Acad Sci U S A. 1986 Oct;83(20):7811-5. doi: 10.1073/pnas.83.20.7811.
Bundle sheath chloroplasts of maize leaves contain about one-fourth as much light-harvesting chlorophyll a/b binding protein of photosystem II (LHCP-II) as do mesophyll chloroplasts. We have determined that this difference is, in part, the result of differential expression of different LHCP-II genes. We have prepared and partially characterized cDNA clones specific for six LHCP-II genes of maize. Transcripts of these six LHCP-II genes are present at vastly different levels and account for about 95% of total LHCP-II mRNAs in bundle sheath and mesophyll cells of illuminated dark-grown maize leaves. Three genes are preferentially expressed in mesophyll cells, and their mRNAs constitute about 54% of the total LHCP-II transcripts in greening (24 hr) maize leaves. Two genes are expressed equally in bundle sheath and mesophyll cells. Most interestingly, the RNA of one gene that contributes about 8% of the total LHCP-II transcripts in leaves greening for 24 hr is present at a much higher level in bundle sheath than in mesophyll cells. Moreover, immunoblot analysis of maize thylakoids reveals at least five sizes of LHCP-II; these also differ from one another in their relative abundance in bundle sheath and mesophyll cells of developing maize leaves.
玉米叶片的维管束鞘叶绿体中光系统II捕光叶绿素a/b结合蛋白（LHCP-II）的含量约为叶肉叶绿体中的四分之一。我们已经确定，这种差异部分是不同LHCP-II基因差异表达的结果。我们制备了玉米六个LHCP-II基因特异性的cDNA克隆，并对其进行了部分表征。这六个LHCP-II基因的转录本水平差异很大，在光照处理的暗生长玉米叶片的维管束鞘和叶肉细胞中约占LHCP-II mRNA总量的95%。三个基因在叶肉细胞中优先表达，它们的mRNA在正在变绿（24小时）的玉米叶片中占LHCP-II转录本总量的约54%。两个基因在维管束鞘和叶肉细胞中表达量相同。最有趣的是，在变绿24小时的叶片中，一个基因的RNA占LHCP-II转录本总量的约8%，其在维管束鞘中的水平远高于叶肉细胞。此外，对玉米类囊体的免疫印迹分析显示至少有五种大小的LHCP-II；它们在发育中的玉米叶片的维管束鞘和叶肉细胞中的相对丰度也彼此不同。
