Hoxb-2 transcriptional activation in rhombomeres 3 and 5 requires an evolutionarily conserved cis-acting element in addition to the Krox-20 binding site.
AUTOR(ES)
Vesque, C
RESUMO
Segmentation is a key feature of the development of the vertebrate hindbrain where it involves the generation of repetitive morphological units termed rhombomeres (r). Hox genes are likely to play an essential role in the specification of segmental identity and we have been investigating their regulation. We show here that the mouse and chicken Hoxb-2 genes are dependent for their expression in r3 and r5 on homologous enhancer elements and on binding to this enhancer of the r3/r5-specific transcriptional activator Krox-20. Among the three Krox-20 binding sites of the mouse Hoxb-2 enhancer, only the high-affinity site is absolutely necessary for activity. In contrast, we have identified an additional cis-acting element, Box1, essential for r3/r5 enhancer activity. It is conserved both in sequence and in position respective to the high-affinity Krox-20 binding site within the mouse and chicken enhancers. Furthermore, a short 44 bp sequence spanning the Box1 and Krox-20 sites can act as an r3/r5 enhancer when oligomerized. Box1 may therefore constitute a recognition sequence for another factor cooperating with Krox-20. Taken together, these data demonstrate the conservation of Hox gene regulation and of Krox-20 function during vertebrate evolution.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=452281Documentos Relacionados
- Errata: Hoxb-2 transcriptional activation in rhombomeres 3 and 5 requires an evolutionarily conserved cis-acting element in addition to the Krox-20 binding site
- cis-acting regulatory elements near the Epstein-Barr virus latent-infection membrane protein transcriptional start site.
- Catabolite repression of the Bacillus subtilis hut operon requires a cis-acting site located downstream of the transcription initiation site.
- An AP-1 binding site is the predominant cis-acting regulatory element in the 1.2-kilobase early RNA promoter of human cytomegalovirus.
- The extrachromosomal replication of Dictyostelium plasmid Ddp2 requires a cis-acting element and a plasmid-encoded trans-acting factor.