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- Variations of SSU rDNA Group I Introns in Different Isolates of Cordyceps militaris and the Loss of an Intron during Cross-Mating
- Tiantian Lian , Tao Yang , Junde Sun , Suping Guo , Huaijun Yang , Caihong Dong
- J. Microbiol. 2014;52(8):659-666. Published online July 4, 2014
- DOI: https://doi.org/10.1007/s12275-014-3681-4
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Abstract
- Cordyceps militaris, the type species of genus Cordyceps, is one of the most popular mushrooms and a nutraceutical in eastern Asia. It is considered a model organism for the study of Cordyceps species because it can complete its life cycle when cultured in vitro. In the present study, the occurrence and sequence variation of SSU rDNA group I introns, Cmi.S943 and Cmi.S1199, among different isolates of C. militaris were analyzed. Based on the secondary structure predictions, the Cmi.S943 intron has been placed in subgroup IC1, and the Cmi.S1199 intron has been placed in subgroup IE. No significant similarity between Cmi.S943 and Cmi.S1199 suggested different origins. Three genotypes, based on the frequency and distribution of introns, were described to discriminate the 57 surveyed C. militaris strains. It was found that the genotype was related to the stroma characteristics. The stromata of all of the genotype II strains, which possessed only Cmi.S943, could produce perithecium. In contrast, the stromata of all genotype III strains, which had both Cmi.S943 and Cmi.S1199, could not produce perithecium. Cmi.S1199 showed the lowest level of intra-specific variation among the tested strains. Group I introns can be lost during strain cross-mating. Therefore, we presumed that during cross-mating and recombination, intron loss could be driven by positive Darwinian selection due to the energetic cost of transcribing long introns.
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Citations
Citations to this article as recorded by
- Gohteikhimyces, a novel hyphomycete genus from submerged wood, based on three collections in Taiwan
Jie-Hao Ou, Sung-Yuan Hsieh, Chang-Hsin Kuo
Mycological Progress.2024;[Epub] CrossRef - Entomopathogenicity of Ascomycete Fungus Cordyceps militaris on the Cotton Bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae)
James P. Glover, Marissa I. Nufer, Omaththage P. Perera, Maribel Portilla, Justin George
Journal of Fungi.2023; 9(6): 614. CrossRef - Comparison of mitochondrial genomes provides insights into intron dynamics and evolution in the caterpillar fungus Cordyceps militaris
Yongjie Zhang, Shu Zhang, Guozhen Zhang, Xingzhong Liu, Chengshu Wang, Jianping Xu
Fungal Genetics and Biology.2015; 77: 95. CrossRef -
Rhf1 gene is involved in the fruiting body production of Cordyceps militaris fungus
Keqing Jiang, Richou Han
Journal of Industrial Microbiology and Biotechnology.2015; 42(8): 1183. CrossRef
- Gohteikhimyces, a novel hyphomycete genus from submerged wood, based on three collections in Taiwan
- Sequence Analysis of the Latent Membrane Protein 1 Genes of Epstein-Barr Virus isolataes in Korea
- Cho, Shin , Cho, Sung Gyu , Shim, Young Shik , Lee, Won Keun
- J. Microbiol. 1998;36(2):130-138.
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Abstract
- The Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is essential for Blymphocyte transformation, and activates NF-kB transcription factior in lymphocytes. LMP1 genes were isolated and sequenced from three type 1 isolates (SNU-321, SNU-538, and SNU-1103) and a type 2 isolate (SNU-20), all derived from Korean cancer pstients, to assess sequence variations in the LMP1 of Korean EBV isolates. Sequence analysis revealed that the SNU-1103 and SNU-20 LNP1 genes were nearly identical to that of the prototype B95-8 type 1 EBV strain, with 98% and 96% identities at the nucleotide and protein level, respectively. The SNU-321 and SNU-538 type 1 LMP1 genes both had a G to T substitution at nucleotide position 169,426, resulting in the loss of a XhoI site, and a carboxy-termina 30 base pair deletion (position 168,287-168,256), indicating they were variant LMP1 genes, as initially described in a Chinese nasopharyngeal carcinoma-derived EBV isolate (CAO). These two variant LMP1 genes shared more sequence variations than the SNU-20 and SNU-1103 IMP1 geres presumably associated with the LMP1 XhoI polymorphism, and showed 96% and 94% sequence identities, respectively, at the nucleotide and amino acid level to respective sequences of B95-8. There were consistent variations between all four isolates and B95-8, including 8-amino acid changes (B95-8 residues 85, 122, 129, 222, 309, 312, 334, 338, and 366) and a 5-amino acid deletion in the carboxy-terminal third 11-amino acid repeat. Transfection of each of these cloned LMP1 genes into Jurkat cells resulted in tenfold stimulation of NF-kB activity, confirming functionality of LMP1 proteins expressed from these genes. Taken together, these results indicate that there is a high degree of overall conservation in sequences of LMP1 between different EBV isolates, yet the distinct sequence variation patterns are consistent with the notion that there are at least two distinct LMP1 variants.
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