Interplay of negative and positive signals controls endoderm-specific expression of the ascidian Cititf1 gene promoter.
Cititf1 is an early and specific marker of endoderm development in Ciona intestinalis [ Development 126, 5149]. Here, we examine Cititf1 transcriptional regulation focusing in particular on its endodermal restricted expression. Through the analysis of Ciona embryos, electroporated with different portions of Cititf1 5'-flanking region fused to lacZ, we characterized a minimal 300-bp cis-regulatory sequence able to closely reproduce the spatial and temporal expression pattern of the endogenous gene. This enhancer contains at least three distinct regulatory regions, two of which are responsible for activation of transcription in the endoderm and in the mesenchyme, respectively, while the third is a negative control element that represses mesenchyme transcription. We have further defined the sequences responsible for transcriptional activation in the endoderm by clustered point mutations and DNA-binding assays.
Laboratory of Biochemistry and Molecular Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy.
Albertina
A
Fanelli
Gabriella
G
Lania
Antonietta
A
Spagnuolo
Roberto
R
Di Lauro
D000818:Animals; D001483:Base Sequence; D004707:Endoderm / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D008648:Mesoderm / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D014561:Urochordata / Q000196:embryology*
C401581:Cititf1 protein, Ciona intestinalis; D018398:Homeodomain Proteins; D014157:Transcription Factors