The telomere-linked helicase (TLH) gene family in Magnaporthe oryzae: revised gene structure reveals a novel TLH-specific protein motif.
Telomere-linked RecQ helicase (TLH) genes have been identified in several fungi, where they occur as small gene families with each member copy residing within ~10 kb of a telomere. Here we describe the characterization of all 11 TLH gene copies in the reference strain of the fungus Magnaporthe oryzae. A consensus gene prediction revealed that the previously reported TLH1 gene is actually a mutated copy, and the full-length gene is almost two times longer. Only four full-length TLH genes were present in the strain that was analyzed, with the remaining copies containing premature stops caused by point mutations, indels, transposon insertions, and a telomere truncation. Interestingly, all of the TLH gene copies possessed numerous mutations indicative of the action of the repeat-induced point mutation process. However, there was evidence of purifying selection indicating maintenance of gene function. Alignment of full-length proteins from M. oryzae, Schizosaccharomyces pombe and M. anisopliae revealed the presence of a novel, highly conserved protein motif which suggests that the telomere-linked helicases have different functions and/or substrates to the RecQ helicases encoded by "internal" genes.
Rehmeyer
Cathryn J
CJ
Department of Plant Pathology, University of Kentucky, Lexington, 40546, USA. farman@email.uky.edu
Li
Weixi
W
Kusaba
Motoaki
M
Farman
Mark L
ML
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D015825:Chromosomes, Fungal / Q000235:genetics; D017124:Conserved Sequence; D004251:DNA Transposable Elements / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D018628:Gene Dosage; D020082:Magnaporthe / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009154:Mutation; D053484:RecQ Helicases / Q000235:genetics* / Q000378:metabolism; D012641:Selection, Genetic; D016415:Sequence Alignment / Q000379:methods; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D016615:Telomere / Q000201:enzymology / Q000235:genetics*
D004251:DNA Transposable Elements; D005656:Fungal Proteins; D053484:RecQ Helicases