Organization and parent-of-origin-specific methylation of imprinted Peg3 gene on mouse proximal chromosome 7.
Peg3 is the first imprinted gene to be identified on mouse proximal chromosome 7; the human PEG3 homologue is on chromosome 19q13.4. Peg3 encodes a C(2)H(2)-type zinc finger protein that is expressed only from the paternal allele in embryos and adult brain. The gene has been shown to regulate maternal behavior and offspring growth and has been implicated in the TNF-NFkappaB signal pathway. Here we show that Peg3 consists of nine exons spanning 26 kb. The 5' region of the gene contains a region rich in repeated sequences and a CpG island. Analysis of expressed sequence tags revealed a transcript present upstream of the island and on the strand opposite to Peg3. These structural features and DNA sequences are conserved in mouse and human. The 5' region of Peg3 is preferentially methylated on the inactive maternal allele, as shown by comparing embryos with paternal (PatDp. prox7) and maternal (MatDp.prox7) duplication of proximal chromosome 7. Recently, a new maternally expressed Zim1 gene located downstream of Peg3 was identified, which suggested that another imprinted cluster is present on proximal chromosome 7.
Li
L L
LL
Wellcome/CRC Institute of Cancer and Developmental Biology, University of Cambridge, Cambridge, CB2 1QR, United Kingdom.
Szeto
I Y
IY
Cattanach
B M
BM
Ishino
F
F
Surani
M A
MA
D000818:Animals; D002875:Chromosomes / Q000737:chemistry*; D002888:Chromosomes, Human, Pair 19 / Q000235:genetics; D018899:CpG Islands; D019175:DNA Methylation; D005314:Embryonic and Fetal Development / Q000235:genetics; D005091:Exons / Q000235:genetics; D005260:Female; D005326:Fetal Proteins / Q000096:biosynthesis / Q000235:genetics; D020440:Gene Duplication; D018507:Gene Expression Regulation, Developmental; D018392:Genomic Imprinting; D006801:Humans; D007438:Introns / Q000235:genetics; D051741:Kruppel-Like Transcription Factors; D008297:Male; D051379:Mice / Q000235:genetics*; D008969:Molecular Sequence Data; D011494:Protein Kinases; D011506:Proteins / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity; D014157:Transcription Factors
D005326:Fetal Proteins; D051741:Kruppel-Like Transcription Factors; C490820:PEG3 protein, human; C097901:Peg3 protein, mouse; D011506:Proteins; D014157:Transcription Factors; D011494:Protein Kinases