【文章名】Comparative genomics approach to the expression of fig alpha, one of the earliest marker genes of oocyte differentiation in medaka (Oryzias latipes)
[摘要]：We analyzed molecular cascades of sex differentiation in medaka gonads by examining the transcriptional regulation of the oocyte-expressed gene, fig alpha. We first confirmed that figa is one of the earliest marker genes of oocyte differentiation by quantitative RT-PCR and in situ hybridization. Expression of putative figa target genes, zpc4 and zpb, followed that of figa alpha. A meiosis-specific gene, scp3, showed expression temporally and spatially similar to fig alpha. To characterize the cis-regulatory sequences of fig alpha, we compared genomic organizations of vertebrate fig alpha genes. Both number and sequence homology of the C-terminal exons showed divergence. suggesting their less important roles. In the frog, Xenopus tropicalis, and in many teleosts, fig alpha is located between hexokinase 2 and beta-adducin. We compared this genomic region for potential cis-regulatory elements and found no DNA stretches with high homology. In spite of this lack of sequence similarities, fluorescent protein transgenes surrounded with fig alpha flanking sequences from the compact genomes of fugu or Tetroodon faithfully reproduced the endogenous expression of fig alpha in the medaka oocytes, indicating conserved regulatory mechanisms. (c) 2008 Elsevier B.V. All rights reserved.
