Nishida K, Adachi W, Shimizu-Matsumoto A, Kinoshita S, Mizuno K, Matsubara K, Okubo K
Department of Ophthalmology, Kyoto Prefectural University of Medicine, Japan.
Invest Ophthalmol Vis Sci. 1996 Aug;37(9):1800-9.
To describe the quantitative and qualitative aspects of gene expression in human corneal epithelium and to discover novel cornea-specific genes.
A 3'-directed cDNA library was constructed with messenger RNA prepared from normal human corneal epithelial cells, and inserts in 1069 randomly chosen clones were sequenced. These sequences were compared with each other to determine the frequency of appearance and were searched against GenBank for identification. The resultant expression profile, a list of gene species and their recurrences, reflected the composition of mRNA in the cornea. Recurrently appearing sequences, representing abundant transcripts, were compared with sequences in expression profiles obtained from seven other tissues and from those in dbEST to discover cornea-specific genes.
The expression profile of human corneal epithelium showed that the most abundant transcript in this tissue was that for apolipoprotein J. Altogether 62 genes were suggested to be very active, including calcyclin, alpha-enolase, keratin 3, connexin 43, and 12 novel genes. The expression of four of these 12 novel genes seemed to be limited to cornea because they were not found in seven other expression profiles nor in dbEST. Full-length cDNA corresponding to one of these (GS8025), isolated from a separately made cDNA library, contained open reading frame highly homologous to mouse keratin 12, which is known to be cornea specific.
An expression profile of corneal epithelium provides probes to monitor physiological and pathologic conditions of this tissue in terms of gene expression. Furthermore, by comparing this profile with those of other tissues, probes to isolate genes uniquely transcribed in corneal epithelium are determined. These genes are assumed to carry unique functions for this tissue and are candidate genes for inherited diseases that manifest only in cornea. As an example, human cornea-specific keratin was isolated, and partial cDNA sequences for three more cornea-specific genes were presented.
描述人角膜上皮中基因表达的定量和定性方面，并发现新的角膜特异性基因。
用从正常人角膜上皮细胞制备的信使核糖核酸构建一个3'端定向的互补脱氧核糖核酸文库，并对随机选择的1069个克隆中的插入片段进行测序。将这些序列相互比较以确定出现频率，并在基因库中进行搜索以进行鉴定。所得的表达谱，即基因种类及其重复出现情况的列表，反映了角膜中信使核糖核酸的组成。将代表丰富转录本的反复出现的序列与从其他七个组织获得的表达谱中的序列以及数据库中表达序列标签（dbEST）中的序列进行比较，以发现角膜特异性基因。
人角膜上皮的表达谱显示，该组织中最丰富的转录本是载脂蛋白J的转录本。总共62个基因被认为是非常活跃的，包括钙周期蛋白、α-烯醇化酶、角蛋白3、连接蛋白43以及12个新基因。这12个新基因中的4个基因的表达似乎仅限于角膜，因为在其他七个表达谱中以及在dbEST中均未发现它们。从另一个单独构建的互补脱氧核糖核酸文库中分离出的与其中一个基因（GS8025）对应的全长互补脱氧核糖核酸，包含与已知为角膜特异性的小鼠角蛋白12高度同源的开放阅读框。
角膜上皮的表达谱提供了从基因表达方面监测该组织生理和病理状况的探针。此外，通过将该表达谱与其他组织进行比较，确定了用于分离在角膜上皮中独特转录的基因的探针。这些基因被认为对该组织具有独特功能，并且是仅在角膜中表现出的遗传性疾病的候选基因。例如，分离出了人角膜特异性角蛋白，并给出了另外三个角膜特异性基因的部分互补脱氧核糖核酸序列。
