Abstract
Abstract: :
Purpose: To identify mRNA’s present in the embryologically related (Pax–6+) conjunctival (Cnj) and corneal (Co) epithelia (E) and the gene subsets that are mutually exclusive. Methods: Biotinylated cDNA derived from fresh, pure CnjE and CoE was hybridized to Human Genome U133A oligonucleotide arrays (Affymetrix). The presence (P) and/or absence (A) and relative abundance of over 16, 000 genes was analyzed using Affymetrix Microarray Suite, version 5.0. Ratios (CnjE/CoE or vice versa) were only calculated, if, in at least one of the two tissues, the expression level exceeded 1% of the overall maximum observed (K12 in CoE). Results: Approximately, 11,593 and 11,375 transcripts (about 8, 433 and 8, 273 genes) were identified in the CnjE and CoE, respectively. As determined by P/A calls and ratios (> 2) 256 transcripts were present exclusively in the CnjE and, conversely 181 transcripts were present only in the CoE. Where transcripts were expressed in both tissues, 119 and 148 displayed CnjE/CoE and CoE/CnjE expression ratios (R) in excess of 3, respectively. The respective subsets for R > 10 contained 19 and 15 transcripts, respectively. Conclusions: Gene expression profiling demonstrates that the phenotypic difference between the two ocular surface epithelia is underpinned by a large number of genes that are either absent in one of the two tissues or present at very distinct levels.
Keywords: cornea: epithelium • conjunctiva • cornea: basic science