Expression of the Vax family homeobox genes suggests multiple roles in eye development.
BACKGROUND
Homeobox gene products are thought to regulate target genes involved in the regional specification of tissues and organs. Several genes play roles in eye development.


RESULTS
We isolated two new mouse homeobox genes, Vax1 and Vax2, expressed in retina primordium. The two genes share the same gene organization, consisting of three exons with predicted amino acid sequences identical in the homeodomain but diversified in other regions. At 9. 5 days post coitum, both Vax genes were expressed in optic vesicles. At 11.5-14.5 dpc, Vax1 became restricted to the optic stalk, while Vax2 was expressed in the ventral half of the neural retina. Mapping of Vax2 between D6Mit3 and D6Mit8 on chromosome 6 indicated a possible linkage with Emx1.


CONCLUSIONS
The expression patterns of Vax genes suggest separate and specific involvement in eye development. Vax1 may contribute to differentiation of the neuroretina, pigmented epithelium and optic stalk, while Vax2 could function in the establishment of the dorso-ventral axis of the retina and the visual system. The chromosomal location of Vax2 suggests that Vax2-Emx1 and Vax1-Emx2 arose by chromosome duplication of the same ancestral gene.
Ohsaki
K
K
Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0101, Japan.
Morimitsu
T
T
Ishida
Y
Y
Kominami
R
R
Takahashi
N
N
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004247:DNA / Q000737:chemistry / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004622:Embryo, Mammalian / Q000378:metabolism; D005314:Embryonic and Fetal Development; D005123:Eye / Q000196:embryology / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox / Q000235:genetics* / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D029867:Xenopus Proteins
D018076:DNA, Complementary; D018398:Homeodomain Proteins; D009479:Neuropeptides; C492362:VAX2 protein, human; C485177:Vax1 protein, mouse; C120595:Vax2 protein, mouse; D029867:Xenopus Proteins; C492361:vax2 protein, Xenopus; D004247:DNA