Cloning and expression of the surfeit locus member Surf-6 during embryogenesis in Xenopus laevis

The Surf-6 gene, already characterized in fish (Fugu rubripes), mouse and man, is a member of the surfeit locus and encodes a nucleolar-matrix protein, which is ubiquitously expressed. This gene has been isolated in Xenopus laevis and shows high sequence similarity to its orthologues in other species. The putative protein is 342 amino acids long and several motifs are conserved, particularly a potential nuclear localization signal. During embryogenesis, after an initial decrease in the expression of the maternal Surf-6 RNA, the level increases to reach a maximum at hatching. The global level of the Surf-6 transcript at early neurula is enhanced by the overexpression of fli, a member of the ets gene family.