Transcriptional regulation of Xbr-1a/Xvent-2 homeobox gene: analysis of its promoter region.
Xvent homeobox proteins are induced by BMP-4 signaling and have been known to mediate many BMP-4 activities as key downstream transcriptional factors. In order to investigate the regulatory mode of Xvent transcription, we isolated genomic DNA of the Xbr-1a/Xvent-2 containing the promoter region responsive to BMP-4 signaling. The cis-acting elements located within the Xbr-1a/Xvent-2 promoter and the regulation modes by BMP-4 signaling were analyzed by serial deletion and site-directed mutagenesis experiments. The upstream -235bp of the promoter retained the full transcriptional activity and BMP-4-response when compared with the longest promoter construct. Further analysis indicated that two separated 15bp regions contained a strong positive element and BMP-4-response element. Site-directed mutagenesis of those regions suggests that those two regions cooperate for the promoter activity and BMP-4-response. Moreover, we found that the transcription factors, Oaz and PEBP2alphaA, were able to elicit additive effects with BMP-4 signaling on Xbr-1a/Xvent-2 reporter activities. These results indicate that transcriptional regulation of the Xbr-1a/Xvent-2 gene occurs in a complex mode through the cooperation of various transcription factors.
Lee
Hyun-Shik
HS
Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, Republic of Korea.
Park
Mae Ja
MJ
Lee
Sung-Young
SY
Hwang
Yoo-Seok
YS
Lee
Hyosang
H
Roh
Dong-Hyun
DH
Kim
Jong-Il
JI
Park
Jae-Bong
JB
Lee
Jae-Yong
JY
Kung
Hsiang-fu
HF
Kim
Jaebong
J
D000818:Animals; D001483:Base Sequence; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics*; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction; D014157:Transcription Factors; D014158:Transcription, Genetic; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics* / Q000378:metabolism
D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D018076:DNA, Complementary; D005136:Eye Proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; C098679:Xbr-1 protein, Xenopus; D029867:Xenopus Proteins; C525812:bmp4 protein, Xenopus; C099992:ventx2.1 protein, Xenopus