Regulatory elements controlling Ci-msxb tissue-specific expression during Ciona intestinalis embryonic development.
The msh/Msx family is a subclass of homeobox-containing genes suggested to perform a conserved function in the patterning of the early embryo. We had already isolated a member of this gene family (Ci-msxb) in Ciona intestinalis, which has a very complex expression pattern during embryogenesis. To identify the regulatory elements controlling its tissue-specific expression, we have characterized the gene structure and the regulatory upstream region. By electroporation experiments, we demonstrated that a 3.8-kb region located upstream of the gene contains all the regulatory elements able to reproduce its spatial expression pattern. Analyzing progressively truncated fragments of this region, three discrete and separate regions driving LacZ reporter gene expression in the ventral epidermis, primordial pharynx and neural territories have been identified. We further investigated the element(s) necessary for Ci-msxb activation in the nervous system during embryonic development by in vivo and in vitro experiments. Both electroporation and gel-shift assays of overlapping wild type and mutated oligonucleotides demonstrated that a unique sequence of 30 bp is involved in Ci-msxb neural activation from neurula to larva stage. This sequence contains consensus binding sites for various ubiquitous transcription factors such as TCF11 whose possible implication in formation of the regulatory complexes is discussed.
Russo
Monia Teresa
MT
Laboratory of Biochemistry and Molecular Biology, Stazione Zoologica "A. Dohrn", Naples 80121, Italy.
Donizetti
Aldo
A
Locascio
Annamaria
A
D'Aniello
Salvatore
S
Amoroso
Alessandro
A
Aniello
Francesco
F
Fucci
Laura
L
Branno
Margherita
M
D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002938:Ciona intestinalis / Q000196:embryology*; D024202:Electrophoretic Mobility Shift Assay; D018274:Electroporation; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D007558:Italy; D007763:Lac Operon / Q000235:genetics; D008969:Molecular Sequence Data; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism
D018398:Homeodomain Proteins; D014157:Transcription Factors