Mechanisms controlling Pax6 isoform expression in the retina have been conserved between teleosts and mammals.
The Pax6 gene plays several roles in retinal development, including control of cell proliferation, maintenance of the retinogenic potential of progenitor cells, and cell fate specification. Emerging evidence suggests that these different aspects of Pax6 gene function are mediated by different isoforms of the Pax6 protein; however, relatively little is known about the spatiotemporal expression of Pax6 isoforms in the vertebrate retina. Using bacterial artificial chromosome (BAC) technology, we modified a zebrafish Pax6a BAC such that we could distinguish paired-containing Pax6a transcripts from paired-less Pax6a transcripts. In the zebrafish, the spatial and temporal onset of expression of these transcripts suggests that the paired-less isoform is involved in the cell fate decision leading to the generation of amacrine cells; however, because of limitations associated with transient transgenic analysis, it was not feasible to establish whether this promoter was active in all amacrine cells or in a specific population of amacrine cells. By making mice transgenic for the zebrafish Pax6a BAC reporter transgene, we were able to show that paired-containing and paired-less Pax6a transcripts were differentially expressed in amacrine subpopulations. Our study also directly demonstrates the functional conservation of the regulatory mechanisms governing Pax6 transcription in teleosts and mammals.
Lakowski
Jörn
J
Department of Cellular Biology, The University of Georgia, Athens, GA 30602, USA.
Majumder
Anirban
A
Lauderdale
James D
JD
D025042:Amacrine Cells / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D017124:Conserved Sequence; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D005136:Eye Proteins / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D008164:Luminescent Proteins / Q000235:genetics; D008322:Mammals / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009457:Neuroglia / Q000378:metabolism; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics*; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D012160:Retina / Q000166:cytology / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism*; D051245:Retinal Bipolar Cells / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics*
D017931:DNA Primers; D005136:Eye Proteins; D018398:Homeodomain Proteins; D008164:Luminescent Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; C000605732:Pax6 protein, mouse; D020033:Protein Isoforms; D011994:Recombinant Proteins; D012097:Repressor Proteins; D029961:Zebrafish Proteins; C485184:enhanced green fluorescent protein; C413663:fluorescent protein 583; D049452:Green Fluorescent Proteins