Active repression of organizer genes by C-terminal domain of PV.1.
PV.1, a homeotic protein, ventralizes dorsal mesoderm and inhibits neuralization by mediating BMP-4 signaling in Xenopus embryo. In our previous report antimorphic PV.1 causes a secondary axis by inducing the ectopic organizer. We analyzed the structure of this transcription factor through domain level assessment. In a phenotype-inducing test, half of the N-terminus at the N-terminal side was unessential for inducing ventralization of embryos. We examined the transacting activity of several regions of PV.1 utilizing GAL4 hybrid system. The C-terminal region/GAL4DBD (DNA binding domain) exhibited strong repressive activity on a reporter gene (operator/promoter/reporter; Gal4-TK-luc) as much as the whole polypeptide/GAL4DBD, whereas the N-terminal region/GAL4DBD showed only modest repression. The results suggest that PV.1 functions as a transcriptional repressor and this repressive activity is localized mostly to the C-terminal region. Additional characterizations of N- and C-terminus with respect to the effects on the expression of other genes are described.
Hwang
Yoo-Seok
YS
Department of Anatomy, School of Medicine, Kyungpook National University, Taegu 700-422, South Korea.
Lee
Hyun-Shik
HS
Roh
Dong-Hyun
DH
Cha
Sang- Wook
S
Lee
Sung-Young
SY
Seo
Jeong-Jae
JJ
Kim
Jaebong
J
Park
Mae Ja
MJ
D000818:Animals; D005260:Female; D017353:Gene Deletion; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000235:genetics*; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D029867:Xenopus Proteins; D014982:Xenopus laevis
D018398:Homeodomain Proteins; D029867:Xenopus Proteins; C109693:ventx1.1 protein, Xenopus