Murphy A M, Lee T, Andrews C M, Shilo B Z, Montell D J
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185, USA.
Development. 1995 Aug;121(8):2255-63. doi: 10.1242/dev.121.8.2255.
To investigate the molecular mechanisms responsible for the temporal and spatial control of cell movements during development, we have been studying the migration of a small group of follicle cells, called the border cells, in the Drosophila ovary. Timely initiation of border cell migration requires the product of the slow border cells (slbo) locus, which encodes the Drosophila homolog of the transcription factor C/EBP. Here we report evidence that one target of C/EBP in the control of border cell migration is the FGF receptor homolog encoded by the breathless (btl) locus. btl expression in the ovary was border cell-specific, beginning just prior to the migration, and this expression was reduced in slbo mutants. btl mutations dominantly enhanced the border cell migration defects found in weak slbo alleles. Furthermore, C/EBP-independent btl expression was able to rescue the migration defects of hypomorphic slbo alleles. Purified Drosophila C/EBP bound eight sites in the btl 5' flanking region by DNAse I footprinting. Taken together these results suggest that btl is a key, direct target for C/EBP in the regulation of border cell migration.
为了研究发育过程中细胞运动的时空控制背后的分子机制，我们一直在研究果蝇卵巢中一小群称为边界细胞的卵泡细胞的迁移。边界细胞迁移的及时启动需要慢边界细胞（slbo）基因座的产物，该基因座编码转录因子C/EBP的果蝇同源物。在此我们报告证据表明，C/EBP在控制边界细胞迁移中的一个靶标是由呼吸急促（btl）基因座编码的FGF受体同源物。btl在卵巢中的表达是边界细胞特异性的，在迁移开始前就开始，并且在slbo突变体中这种表达降低。btl突变显著增强了在弱slbo等位基因中发现的边界细胞迁移缺陷。此外，不依赖C/EBP的btl表达能够挽救亚等位基因slbo的迁移缺陷。通过DNA酶I足迹法，纯化的果蝇C/EBP在btl 5'侧翼区域结合了八个位点。综合这些结果表明，btl是C/EBP在调节边界细胞迁移中的一个关键直接靶标。
