Vsx-1 and Vsx-2: differential expression of two paired-like homeobox genes during zebrafish and goldfish retinogenesis.
Vsx-1 and Vsx-2 are two homeobox genes that were cloned originally from an adult goldfish retinal library. They are members of the paired-like:CVC gene family, which is characterized by the presence of a paired homeodomain and an additional conserved region, termed the CVC domain. To analyze the possible roles for Vsx-1 and Vsx-2 in eye development, we used in situ hybridization to examine their expression patterns in zebrafish and goldfish embryos. Vsx-2 is initially expressed by proliferating neuroepithelial cells of the presumptive neural retina, then it is down-regulated as differentiation begins, and it is finally reexpressed at later stages of differentiation in a subset of cells, presumed to be bipolar cells, in the inner nuclear layer. In contrast, Vsx-1 is expressed only weakly in undifferentiated, presumptive neural retina and is then up-regulated selectively in presumptive bipolar cells at early stages of differentiation (when Vsx-2 is turned off), before decreasing to an intermediate level, which is maintained in the differentiated (adult) retina. The restricted expression patterns of Vsx-2 correspond to the observed phenotypes in mice with the ocular retardation mutation (orJ), further supporting the notion that Vsx-2 and Chx10 are homologues. The sequential complimentary and then corresponding expression patterns of Vsx-1 and Vsx-2 suggest that these similar transcription factors may be recruited for partially overlapping, but distinct, functions during the development of the retina.
Passini
M A
MA
Department of Biochemistry and Cell Biology, State University of New York at Stony Brook 11794, USA.
Levine
E M
EM
Canger
A K
AK
Raymond
P A
PA
Schechter
N
N
D000595:Amino Acid Sequence; D000818:Animals; D005123:Eye / Q000196:embryology; D005136:Eye Proteins / Q000235:genetics*; D029941:Fish Proteins; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005801:Genes, Homeobox; D006054:Goldfish / Q000196:embryology / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D012160:Retina / Q000196:embryology / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015027:Zebrafish / Q000196:embryology / Q000235:genetics*; D029961:Zebrafish Proteins
D005136:Eye Proteins; D029941:Fish Proteins; D018398:Homeodomain Proteins; C108839:Vsx-2 protein, Carassius auratus; D029961:Zebrafish Proteins; C108838:vsx1 protein, zebrafish