Two-step regulation and continuous retrotransposition of the rice LINE-type retrotransposon Karma.
Here, we report the identification of Karma, a LINE-type retrotransposon of plants for which continuous retrotransposition was observed in consecutive generations. The transcription of Karma is activated in cultured cells of rice upon DNA hypomethylation. However, transcription is insufficient for retrotransposition, because no increase in the copy number was observed in cultured cells or in the first generation of plants regenerated from them. Despite that finding, copy number increase was detected in the next generation of regenerated plants as well as in later generations, suggesting that the post-transcriptional regulation of Karma retrotransposition is development dependent. Our results indicate that two different mechanisms, one transcriptional and the other developmental, control the mobilization of KARMA: In addition, unlike other known active plant retrotransposons, Karma is not subject to de novo methylation, and retrotransposition persists through several generations.
Komatsu
Mai
M
Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan.
Shimamoto
Ko
K
Kyozuka
Junko
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D019175:DNA Methylation; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020084:Long Interspersed Nucleotide Elements; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014158:Transcription, Genetic
D018744:DNA, Plant; D010940:Plant Proteins