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Title: MG-SINE: A SHORT INTERSPERSED NUCLEAR ELEMENT FROM THE RICE BLAST FUNGUS MAGNAPORTHE GRISEA

Author
item KACHROO, P - UNIVERSITY OF WISCONSIN
item Leong, Sally
item CHATTOO, B - UNIVERSITY OF WISCONSIN

Submitted to: Proceedings of the National Academy of Sciences (PNAS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/28/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: We describe here the discovery of a jumping gene Mg-SINE in Magnaprothe grisea, the casual agent of rice blast disease. Rice blast disease is the most important disease of rice worldwide. As rice feeds two-thirds of the human population, it is important to better understand the basic biology of this fungus. M. grisea is notorious for its ability to change to become more virulent in response to the use of new blast resistant varieties of rice. How this fungus becomes more virulent is largely unknown. Jumping genes are known to cause changes in the genetic material of many different kinds of organisms from bacteria to man. We are investigating the role of jumping genes in the ability of the rice blast fungus to become more virulent. We show here that many copies of Mg-SINE can be found in the genome of the rice blast fungus and that these can also fuse to other DNA sequences in the genome showing the potential of this jumping gene to cause mutations in DNA.

Technical Abstract: A Short Intersperse Nuclear Element, Mg-SINE, was isolated and characterized from the genome of the rice blast fungus Magnaporthe grisea. Mg-SINE was isolated as an insertion element with Pot2, an inverted repeat transposon from M. grisea and shows typical features of a mammalian SINE sequence. The element is present as a 0.47 kb interspersed sequence in approximately 100 copies per haploid genome, in both rice and non-rice pathogens of M. grisea, indicating a common ancestry. Secondary structure analysis of Mg-SINE reveals a t-RNA related region at the 5` end which folds into a clover-leaf like structure. Genomic functions resulting in a chimeric Mg-SINE element (Ch-SINE) composed of a sequence homologous to mg-SINE at 3` end and an unrelated sequence at its 5` end were also isolated, indicating that this and other DNA rearrangements mediated by these elements may have a major effect on the genomic architecture of this fungus.