Expression of the p53 family of proteins in central and peripheral human corneal endothelial cells.
OBJECTIVE
To determine the protein and mRNA expression of p53, p63, and p73 in central and peripheral human corneal endothelial cells. Since these proteins are known to be involved in the regulation of cell division, this study seeks information about their influence in regulating cell proliferation in the human corneal endothelium.


METHODS
Human donor corneas were separated into central and peripheral sections. The endothelial tissue from these samples was dissected and samples were analyzed for mRNA transcription of p53, transactivating p63 (TAp63), delta N p63 (DeltaNp63), transactivating p73 (TAp73), and delta N p73 (DeltaNp73) via the reverse transcriptase-polymerase chain reaction (RT-PCR). Additional samples were analyzed for p53, p63, and p73 protein expression via SDS-PAGE, western blotting, and immunodetection. Frozen corneal sections were immunostained for p53 and analyzed via fluorescence microscopy.


RESULTS
p53 and TAp63 mRNA and protein expression were detected in central and peripheral human corneal endothelium. p53 and TAp63 protein expression were greater in central than in peripheral tissue. DeltaNp63 and all isoforms of p73 were not detected in either central or peripheral corneal endothelium.


CONCLUSIONS
p53 is expressed in both peripheral and central human corneal endothelium, although it is more highly expressed in the central endothelium. Similarly, TAp63 is more highly expressed in central rather than in peripheral endothelium. This suggests that the peripheral endothelium may have more potential for cell division than the central endothelium. DeltaNp63, a stem cell marker, was not detected in the corneal endothelium. Neither the TAp73 nor the DeltaNp73 isoforms were detected in either central or peripheral human corneal endothelium.
Paull
Amanda C
AC
Department of Vision Sciences, Vision Science Research Center, School of Optometry, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Whikehart
David R
DR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D015153:Blotting, Western; D002648:Child; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004728:Endothelium, Corneal / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D016147:Genes, Tumor Suppressor; D006801:Humans; D008875:Middle Aged; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism; D025521:Tumor Suppressor Proteins
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; C115051:TP63 protein, human; C000606460:TP73 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C000606369:delta Np73 protein, human