Pattern of expression of p53, its family members, and regulators during early ocular development and in the post-mitotic retina.
OBJECTIVE
Because of its role in cell cycle regulation and apoptosis, p53 may be involved in maintaining the post-mitotic state of the adult eye. To shed light on the role of p53 in retinal development and maintenance, this study investigated the pattern of expression of p53, its family members, and its regulators during the development of the mouse eye.


METHODS
Relative quantitative real-time PCR (qRT-PCR) was used to determine the steady-state levels of target transcripts in RNA extracted from wild-type mouse whole eyes or retinas between embryonic day (E) 15 and post-natal day (P) 30. Immunoblotting was used to compare the steady-state levels of the protein to that of the transcript.


RESULTS
Transcript and protein levels for p53 in the eye were highest at E17 and E18, respectively. However, both p53 transcript and protein levels dropped precipitously thereafter, and no protein was detected on immunoblots after P3. Expression patterns of p63, p73, Mdm2, Mdm4, and Yy1 did not follow that of p53. Immunohistochemistry analysis of the developing eye showed that both p53 and Mdm2 are abundantly expressed at E18 in all layers of the retinal neuroblast.


CONCLUSIONS
Downregulation of p53 in the post-mitotic retina suggests that, although p53 may be involved in ocular and retinal development, it may play a minimal role in healthy adult retinal function.
Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Linda
L
Vuong
Daniel E
DE
Brobst
Anisse
A
Saadi
Ivana
I
Ivanovic
Muayyad R
MR
Al-Ubaidi
D000818:Animals; D004268:DNA-Binding Proteins / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D016158:Genes, p53 / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012160:Retina / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D050986:YY1 Transcription Factor / Q000378:metabolism
D004268:DNA-Binding Proteins; C461497:Mdm4 protein, mouse; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; C486419:Trp63 protein, mouse; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D050986:YY1 Transcription Factor; C494699:Yy1 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2; D044767:Ubiquitin-Protein Ligases