We describe the temporal and spatial expression pattern of Sox 1 gene during Xenopus laevis early development and compare the expression patterns of Sox 1-3 in the developing eye and brain. Alignment of Sox 1-3 amino acid sequences shows a high conservation within the HMG-box DNA binding domains. RT-PCR analysis indicates that Sox 1 is expressed throughout development from the unfertilized egg to at least the tadpole stage, although at different expression levels. The transcripts of XSox 1 are detected in the animal pole at cleavage and blastrula stages and mainly in the central nervous system （CNS） and the developing eye at neurula stages. The study of the developmental expression of XSox 1 will aid in the elucidation of the function of SoxB 1 subgroup genes in vertebrate neurogenesis.
