Department of Veterinary Biosciences, FI-00014 University of Helsinki, Finland.
Gene. 2012 Jan 1;491(1):65-70. doi: 10.1016/j.gene.2011.08.030. Epub 2011 Sep 16.
MCT1-CD147 complex is the prime lactate transporter in mammalian plasma membranes. In equine red blood cells (RBCs), activity of the complex and expression of MCT1 and CD147 is bimodal; high in 70% and low in 30%. We studied whether sequence variations contribute to the bimodal expression of MCT1 and CD147. Samples of blood and cremaster muscle were collected in connection of castration from 24 horses. Additional gluteus muscle samples were collected from 15 Standardbreds of which seven were known to express low amounts of CD147 in RBCs. The cDNA of MCT1 and CD147 together with a promoter region of CD147 was sequenced. The amounts of MCT1 and CD147 expressed in RBC and muscle membranes were measured by Western blot and mRNA levels in muscles by qPCR. MCT1 and CD147 were expressed in 20 castrates, and in four only were traces found. Sequence variations found in MCT1 were not linked to MCT1 expression. In CD147 linked heterozygous single nucleotide polymorphisms (SNPs) 389A>G (Met(125)Val) and 990C>T (3'-UTR) were associated to low expression of CD147. Also a mutation 168A>G (Ile(51)Val) in CD147 was associated to low MCT1 and CD147 expression. Low MCT1 and CD147 mRNA levels in gluteus were found in Standardbreds with low CD147 expression in RBCs. The results suggest that sequence variations affect the expression level of CD147, but do not explain its bimodality. The levels of MCT1 and CD147 mRNA correlated with the expression of CD147 and suggest that bimodality of their expression is regulated at transcriptional level.
MCT1-CD147 复合物是哺乳动物质膜中主要的乳酸转运体。在马的红细胞（RBC）中，该复合物的活性以及 MCT1 和 CD147 的表达呈双峰模式；70%的红细胞中表达较高，而 30%的红细胞中表达较低。我们研究了序列变异是否导致 MCT1 和 CD147 的双峰表达。在 24 匹马的去势手术中，采集了血液和腹外斜肌样本。从 15 匹标准种马中额外采集了臀肌样本，其中 7 匹已知 RBC 中 CD147 表达量较低。我们对 MCT1 和 CD147 的 cDNA 以及 CD147 的启动子区域进行了测序。通过 Western blot 测量 RBC 和肌肉膜中 MCT1 和 CD147 的表达量，并通过 qPCR 测量肌肉中的 mRNA 水平。在 20 个去势马中检测到了 MCT1 和 CD147 的表达，在 4 个马中仅检测到了痕量表达。在 MCT1 中发现的序列变异与 MCT1 的表达无关。在 CD147 中，连锁的单核苷酸多态性（SNP）389A>G（Met(125)Val）和 990C>T（3'-UTR）与 CD147 的低表达相关。此外，CD147 中的突变 168A>G（Ile(51)Val）也与低 MCT1 和 CD147 表达相关。在 RBC 中 CD147 表达较低的标准种马的臀肌中发现了低 MCT1 和 CD147 mRNA 水平。结果表明，序列变异会影响 CD147 的表达水平，但不能解释其双峰模式。MCT1 和 CD147 mRNA 的水平与 CD147 的表达相关，表明它们表达的双峰模式是在转录水平上受到调节的。
