Comparative genomics approach toward critical determinants for the imprinting of an evolutionarily conserved gene Impact.
The Impact is an evolutionarily conserved gene subjected to genomic imprinting in mouse but not in human. A characteristic tandem repeat similar to those found in many other imprinted genes and an elevated expression level, both observed only for the mouse gene, are implicated in the evolution of imprinting, to which the repeat might have contributed via enhancement of the expression. To pursue the possibility further, we examined the correlation among the repeat, expression level, and imprinting of Impact in various mammals ranging from rodents, lagomorphs, carnivores, artiodactyls to primates. Intriguingly, rabbit Impact is abundantly expressed and imprinted like those of rodents, but is missing the repeat from its first intron like those of other mammals that express both alleles weakly. It thus seems that lineage-specific enhancement of gene expression rather than the tandem repeat per se played a critical role in the evolution of imprinting of Impact.
Okamura
Kohji
K
Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
Sakaki
Yoshiyuki
Y
Ito
Takashi
T
D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping / Q000379:methods*; D017124:Conserved Sequence / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods*; D004285:Dogs; D019143:Evolution, Molecular; D014644:Genetic Variation / Q000235:genetics; D018392:Genomic Imprinting / Q000235:genetics*; D023281:Genomics / Q000379:methods; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008251:Macaca; D008969:Molecular Sequence Data; D011506:Proteins / Q000235:genetics*; D011817:Rabbits; D051381:Rats; D017422:Sequence Analysis, DNA / Q000379:methods*; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D013552:Swine; D020080:Tandem Repeat Sequences
C484600:IMPACT protein, human; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins