Quail Pax-6 (Pax-QNR) mRNAs are expressed from two promoters used differentially during retina development and neuronal differentiation.
During investigations on the regulation of the Pax-6 gene, we characterized a cDNA from quail neuroretina showing a 5' untranslated region distinct from that previously described and initiated from an internal promoter. Using RNase protection and primer extension mapping, we localized this second quail Pax-6 promoter, termed P1. As reported for the already described P0 promoter, P1 was also transactivated in vitro by the p46Pax-QNR protein. RNase protection assays performed with quail neuroretina RNA showed that P1-initiated mRNAs were detected before the P0-initiated mRNAs, remained constant up to embryonic day 8, and decreased slowly thereafter whereas, P0-initiated mRNAs accumulated up to embryonic day 8. In contrast, quail retinal pigmented epithelium expressed only the P1-initiated mRNAs. Transformation of these cells by the v-myc oncogene induced neuronal traits in the culture, which thereafter, in addition to the P1-initiated mRNAs, expressed Pax-QNR from the P0 promoter. These results suggest that expression of the quail Pax-6 gene is under the control of different regulators through alternate promoters, P0 being activated at the onset of neuronal differentiation.
Plaza
S
S
Laboratoire de Différenciation Cellulaire et Moléculaire, CNRS EP56, Institute Pasteur, Lille, France.
Dozier
C
C
Turque
N
N
Saule
S
S
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D002478:Cells, Cultured; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D005136:Eye Proteins; D018398:Homeodomain Proteins; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D011401:Promoter Regions, Genetic / Q000235:genetics; D011784:Quail / Q000196:embryology* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D012097:Repressor Proteins; D012160:Retina / Q000196:embryology* / Q000378:metabolism
D004268:DNA-Binding Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012333:RNA, Messenger; D012097:Repressor Proteins