Abstract
Abstract: :
Purpose: To report gene expression profiles of normal human corneal endothelium using Serial Analysis of Gene Expression (SAGE) and microarray analysis. Methods: Three pairs of normal human corneas were obtained from eye banks. RNA was isolated from the corneal endothelium and analyzed by SAGE and the Affymetrix HGU95A microarray. Results: 9,530 SAGE tags were sequenced, representing 4,724 unique tags/transcripts. 1,720 tags matched known genes, 478 tags matched ESTs, and 2,526 tags had no known match to publicly available databases. Microarray analysis detected the expression of 542 distinct transcripts out of 12,558 total transcripts represented on the chip. One hundred forty five of the UniGene clusters detected by microarray were also detected by SAGE. A preliminary database of human corneal endothelial gene expression was compiled. The 5 most abundantly expressed SAGE tags were cytochrome c oxidase subunit II, ATP synthase FO subunit 6, carbonic anhydrase XII, 12S ribosomal RNA, and ferritin, heavy polypeptide 1. Many endothelial pump function enzymes were confirmed including Na+/K+ ATPases as well as a recently reported bicarbonate transporter. Cell adhesion protein transcripts were noted including actins, cadherin, catenin, vimentin, and connexin. Basement membrane transcripts identified included collagens, keratins, and laminin. Eight of the top 50 most abundantly expressed tags did not match to known genes, indicating that novel genes with unique corneal functions may yet be discovered. When compared to 8 additional SAGE libraries representing other tissue sources, 34% of the transcripts (1,616) were specific to the corneal endothelium. The top 5 most abundant cornea specific tags were, keratin 12, angiopoietin-like factor, annexin A8, and 2 tags with no match to the databases. Conclusion: Corneal endothelial gene expression profiles by SAGE and microarray analysis provide an understanding of endothelial metabolism, structure and function, enable comparisons to diseased endothelial tissues, and provide baseline data which may lead to the study of novel endothelial genes.
Keywords: 417 gene/expression • 371 cornea: endothelium • 370 cornea: basic science