Purpose: The ocular surface epithelia express at least five mucin genes of the total of 17 human mucin genes that have been identified so far. This study was designed to determine the expression profile of mucin genes in conjunctival impression cytology (CIC) samples from healthy subjects.
Methods: Two polyethersulfone filters were applied to the superior conjunctiva of both eyes from eight healthy donors. Polymerase chain reaction (PCR) was performed using isolated and retrotranscripted total RNA obtained from the CIC samples to study the expression of all known human mucin genes. Following amplification, PCR products were electrophoresed on 1.5% agarose gel and stained with ethidium bromide to confirm that only a single band was obtained when amplifying all cDNAs with the convenient primers.
Results: Transcripts of the previously reported conjunctival mucin genes MUC1, MUC2, MUC4, MUC5AC, and MUC7 were detected in all samples. In addition, transcripts of MUC13, MUC15, MUC16 and MUC17 mucin genes also were detected. Amplified products by conventional PCR showed the expected amplicon size. Transcripts of MUC3A, MUC3B, MUC5B, MUC6, MUC8, MUC11, and MUC12 mucin genes were not detected.
Conclusion: The expression of four additional mucin mRNA (MUC13, MUC15, MUC16, and MUC17) has been proved in human conjunctival epithelium from healthy donors for the first time. The function of these genes remains to be further elucidated.