Cole T, Dickson P W, Esnard F, Averill S, Risbridger G P, Gauthier F, Schreiber G
Russell Grimwade School of Biochemistry, University of Melbourne, Australia.
Eur J Biochem. 1989 Dec 8;186(1-2):35-42. doi: 10.1111/j.1432-1033.1989.tb15174.x.
Tissue patterns of gene expression were analyzed by measuring mRNA levels and incorporation of radioactive amino acids for cystatin C and beta 2-microglobulin, the two extracellular proteins in the brain with the highest ratio of concentration in cerebrospinal fluid over that in blood plasma. The primary structure of rat cystatin C mRNA from choroid plexus was determined by nucleotide sequencing of cloned cDNA and the tissue patterns of gene expression were analysed by RNA blot analysis and in situ hybridization. Cystatin C was found to be composed of 120 amino acids and to contain a potential site for N-linked glycosylation. The tissue with the highest cystatin C mRNA level was the choroid plexus of the brain. Cystatin C mRNA was also detected in lower levels in other areas of the brain, testis, epididymis, seminal vesicles, prostate, ovary, submandibular gland, and, in trace amounts, in liver. Choroid plexus pieces in culture secreted radioactive cystatin C when incubated with radioactive leucine. Rat beta 2-microglobulin cDNA was cloned and identified by nucleotide sequencing and comparison of the obtained sequence with that of mouse and human beta 2-microglobulin cDNA. Tissue levels of beta 2-microglobulin mRNA in the rat were measured by hybridization to rat beta 2-microglobulin cDNA. The highest levels of beta 2-microglobulin mRNA were observed in liver and choroid plexus. Other parts of the brain and testis contained lower levels of beta 2-microglobulin mRNA.
通过测量脑脊液中浓度与血浆中浓度比值最高的两种细胞外蛋白——胱抑素C和β2-微球蛋白的mRNA水平以及放射性氨基酸的掺入量，分析了基因表达的组织模式。通过对克隆的cDNA进行核苷酸测序，确定了来自脉络丛的大鼠胱抑素C mRNA的一级结构，并通过RNA印迹分析和原位杂交分析了基因表达的组织模式。发现胱抑素C由120个氨基酸组成，并含有一个潜在的N-连接糖基化位点。胱抑素C mRNA水平最高的组织是脑脉络丛。在脑的其他区域、睾丸、附睾、精囊、前列腺、卵巢、下颌下腺以及肝脏中也检测到较低水平的胱抑素C mRNA。培养的脉络丛碎片与放射性亮氨酸一起孵育时会分泌放射性胱抑素C。通过核苷酸测序以及将所得序列与小鼠和人β2-微球蛋白cDNA序列进行比较，克隆并鉴定了大鼠β2-微球蛋白cDNA。通过与大鼠β2-微球蛋白cDNA杂交，测量了大鼠组织中β2-微球蛋白mRNA的水平。在肝脏和脉络丛中观察到β2-微球蛋白mRNA的最高水平。脑的其他部分和睾丸中β2-微球蛋白mRNA的水平较低。
