Two evolutionarily conserved sequence elements for Peg3/Usp29 transcription.
BACKGROUND
Two evolutionarily Conserved Sequence Elements, CSE1 and CSE2 (YY1 binding sites), are found within the 3.8-kb CpG island surrounding the bidirectional promoter of two imprinted genes, Peg3 (Paternally expressed gene 3) and Usp29 (Ubiquitin-specific protease 29). This CpG island is a likely ICR (Imprinting Control Region) that controls transcription of the 500-kb genomic region of the Peg3 imprinted domain.


RESULTS
The current study investigated the functional roles of CSE1 and CSE2 in the transcriptional control of the two genes, Peg3 and Usp29, using cell line-based promoter assays. The mutation of 6 YY1 binding sites (CSE2) reduced the transcriptional activity of the bidirectional promoter in the Peg3 direction in an orientation-dependent manner, suggesting an activator role for CSE2 (YY1 binding sites). However, the activity in the Usp29 direction was not detectable regardless of the presence/absence of YY1 binding sites. In contrast, mutation of CSE1 increased the transcriptional activity of the promoter in both the Peg3 and Usp29 directions, suggesting a potential repressor role for CSE1. The observed repression by CSE1 was also orientation-dependent. Serial mutational analyses further narrowed down two separate 6-bp-long regions within the 42-bp-long CSE1 which are individually responsible for the repression of Peg3 and Usp29.


CONCLUSIONS
CSE2 (YY1 binding sites) functions as an activator for Peg3 transcription, while CSE1 acts as a repressor for the transcription of both Peg3 and Usp29.
Kim
Jeong Do
JD
Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA. jkim@lsu.edu
Yu
Sungryul
S
Choo
Jung Ha
JH
Kim
Joomyeong
J
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D001665:Binding Sites; D017124:Conserved Sequence / Q000235:genetics; D010450:Endopeptidases / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D023061:Gene Order; D006367:HeLa Cells; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D015533:Transcriptional Activation / Q000235:genetics; D064570:Ubiquitin-Specific Proteases; D050986:YY1 Transcription Factor / Q000378:metabolism
D051741:Kruppel-Like Transcription Factors; C097901:Peg3 protein, mouse; D050986:YY1 Transcription Factor; D010450:Endopeptidases; C579223:USP29 protein, human; D064570:Ubiquitin-Specific Proteases; C579222:Usp29 protein, mouse