• Title/Summary/Keyword: Intron

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Morphological and molecular evidence of the hybrid origin of Crepidiastrum ×muratagenii in Korea (홍도고들빼기의 형태 다양성 및 잡종 기원의 분자 증거)

  • JANG, Young-Jong;PARK, Boem Kyun;SON, Dong Chan;CHOI, Byoung-Hee
    • Korean Journal of Plant Taxonomy
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    • v.52 no.2
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    • pp.85-96
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    • 2022
  • The plant "Hong-do-go-deul-ppae-gi" has been considered as Crepidiastrum × muratagenii, a hybrid between C. denticulatum and C. lanceolatum, based on its morphological traits and geographical distribution. To reveal the hybrid origin of Hong-do-go-deul-ppae-gi, we examined additional morphological traits of this plant and its putative parents (C. denticulatum, C. lanceolatum, C. platyphyllum) and analyzed one nuclear ribosomal internal transcribed spacer (ITS) region and four chloroplast regions (trnT-L, trnL-F, rpl16 intron, and rps16 intron). As a result of examining the morphological traits, putative hybrid individuals were classified into three types based on the habit, cauline leaf, outer phyllary, and achene beak traits. A molecular analysis found that the ITS sequences of Type 1 and Type 2 individuals showed additive species-specific sites of C. denticulatum and C. lanceolatum. Plastid sequences of Type 1 and Type 2 individuals showed C. denticulatum and C. lanceolatum sequences, respectively. However, Type 3 individuals had ITS and plastid sequences corresponding to C. denticulatum. Accordingly, Type 1 and Type 2 individuals not only share morphological traits with C. denticulatum and C. lanceolatum but also show additive species-specific sites for C. denticulatum and C. lanceolatum, and not C. platyphyllum, supporting its origin as a hybrid between C. denticulatum and C. lanceolatum. Type 3 had morphological traits similar to other hybrid types but was distinguished with respect to outer phyllaries and demonstrated some resemblance to C. denticulatum. In a molecular analysis, Type 3 was found to be identical with regard to the sequence of C. denticulatum and was judged to be an ecological variation of C. denticulatum.

Thermodynamic Analyses of the Constitutive Splicing Pathway for Ovomucoid Pre-mRNA

  • Ro-Choi, Tae Suk;Choi, Yong Chun
    • Molecules and Cells
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    • v.27 no.6
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    • pp.657-665
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    • 2009
  • The ovomucoid pre-mRNA has been folded into mini-hairpins adaptable for the RNA recognition motif (RRM) protein binding. The number of mini-hairpins were 372 for pre-mRNA and 83-86 for mature mRNA. The spatial arrangements are, in average, 16 nucleotides per mini-hairpin which includes 7 nt in the stem, 5.6 nt in the loop and 3.7 nt in the inter-hairpin spacer. The constitutive splicing system of ovomucoid-pre-mRNA is characterized by preferred order of intron removal of 5/6 > 7/4 > 2/1 > 3. The 5' splice sites (5'SS), branch point sequences (BPS) and 3' splice sites (3'SS) were identified and free energies involved have been estimated in 7 splice sites. Thermodynamic barriers for splice sites from the least (|lowest| -Kcal) were 5, 4, 7, 6, 2, 1, and 3; i.e., -18.7 Kcal, -20.2 Kcal, -21.0 Kcal, -24.0 Kcal, - 25.4 Kcal, -26.4 Kcal and -28.2 Kcal respectively. These are parallel to the kinetic data of splicing order reported in the literature. As a result, the preferred order of intron removals can be described by a consideration of free energy changes involved in the spliceosomal assembly pathway. This finding is consistent with the validity of hnRNP formation mechanisms in previous reports.

Isoform-specific response of two GAPDH paralogs during bacterial challenge and metal exposure in mud loach (Misgurnus mizolepis: Cypriniformes) kidney and spleen

  • Cho, Young-Sun;Kim, Dong-Soo;Nam, Yoon-Kwon
    • Journal of fish pathology
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    • v.24 no.3
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    • pp.269-278
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    • 2011
  • Gene expression of two glyceraldehyde-3-phosphate dehydrogenase (GAPDH) paralogs was examined during Edwardsiella tarda challenge and heavy metal exposures in mud loach (Misgurnus mizolepis; Cypriniformes) kidney and spleen. Transcription of the two mud loach GAPDH paralogs (mlGAPDH-1 and mlGAPDH-2) was significantly modulated by these stimulatory challenges in an isoform-dependent manner. Based on the real-time RT-PCR analysis, the mlGAPDH-2 transcripts were more preferentially induced by E. tarda challenge, whereas the mlGAPDH-1 transcripts were proven to show more inducibility in response to heavy metal exposure using Cd, Cu, Mn and Zn at $5{\mu}M$. Their isoform-specific response patterns were closely in accordance with the TF binding profiles in promoter and intron-1 of the two mlGAPDH isoforms, in which the mlGAPDH-2 has more binding sites for immune-related transcription factors than mlGAPDH-1 while the mlGAPDH-1 possesses exclusively metal responsive elements in its intron. Collectively, the mlGAPDHs are potentially involved in cellular pathways independent of glycolysis and the two GAPDH paralogs might undergo functional diversification or subfunctionalization at least at the transcription level.

Transposition of IntAs into the Conserved Regions of IS3 Family Elements

  • Han, Chang-Gyun
    • Journal of Microbiology
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    • v.42 no.1
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    • pp.56-59
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    • 2004
  • Together with the previous reports, my computer survey revealed that several bacteria contain six copies of the type group II intron IntA. The sequence analysis of IntAs showed the high level of homology in the nucleotide sequence (91.9-99.8%). The consensus sequence, 2,270 base pair long, was derived from the nucleotide sequences of all IntA members. The size of the open reading frame intA was 502 amino acids long, that is homologous to reverse transcriptase-like proteins encoded within the group II introns. It was reported that EPEC.IntA and Sf.IntA were inserted into IS911 and IS629, respectively. The sequence of the flanking region IntA was analyzed here. The data show the insertion of EC.IntA into IS629, the insertion of EHEC.IntA into IS3, the insertion of Yp.IntA into IS904-like sequence, and the insertion of EK12.IntA into IS911. Interestingly, these IS elements nested by IntAs were the members of IS3 family elements. The sequences of the IS3 members correspond to the OrfB with the DDE motif conserved in retroviral integrases. Alignment of the flanking sequences of IntAs revealed that the flanking regions -25 to + 10 of insertion sites, that are generally believed to be required for the retrohoming, were not strongly conserved. The data presented here suggests that the retrohoming pathway of IntA seems to differ from those of other group II introns.

Intraspecific variation of gene structure in the mitochondrial large subunit ribosomal RNA and cytochrome c oxidase subunit 1 of Pyropia yezoensis (Bangiales, Rhodophyta)

  • Hwang, Il Ki;Kim, Seung-Oh;Hwang, Mi Sook;Park, Eun-Jeong;Ha, Dong-Soo;Lee, Sang-Rae
    • ALGAE
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    • v.33 no.1
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    • pp.49-54
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    • 2018
  • Red algal mitochondrial genomes (mtDNAs) can provide useful information on species identification. mtDNAs of Pyropia / Porphyra (Bangiales, Rhodophyta) have shown diverse variation in their size and gene structure. In particular, the introns and intronic open reading frames found in the ribosomal RNA large subunit gene (rnl) and cytochrome c oxidase subunit 1 gene (cox1) significantly vary the mitochondrial genome size in Pyropia / Porphyra species. In this study, we examined the exon / intron structure of rnl and cox1 genes of Pyropia yezoensis at the intraspecific level. The combined data of rnl and cox1 genes exhibited 12 genotypes for 40 P. yezoensis strains, based on the existence of introns. These genotypes were more effective to identify P. yezoensis strains in comparison to the traditional DNA barcode cox1 marker (5 haplotypes). Therefore, the variation in gene structure of rnl and cox1 can be a novel molecular marker to discriminate the strains of Pyropia species.

Genomic Organization, Intronic Duplications, and Promoter Characteristics of the Fast Skeletal Myosin Light Chain-2 Gene (mlc2f) from Javanese Ricefish Oryzias javanicus

  • Lee, Sang Yoon;Kim, Dong Soo;Nam, Yoon Kwon
    • Fisheries and Aquatic Sciences
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    • v.15 no.4
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    • pp.325-335
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    • 2012
  • The present study characterized the fast skeletal myosin light chain-2 gene (mlc2f) in the euryhaline Javanese ricefish (Oryzias javanicus: Beloniformes). Coding nucleotide and deduced amino acid sequences of Javanese ricefish mlc2f were well conserved in the vertebrate lineage. Javanese ricefish mlc2f showed a typical seven-exon structure, and its promoter exhibited transcription factor binding motifs common to most muscle-specific genes. However, Javanese ricefish mlc2f also displayed tandem duplications of intronic sequences in both intron 1 and intron 3. Based on quantitative reverse transcription-polymerase chain reaction, the mlc2f transcripts were highly predominant in skeletal muscles of adults and were differentially modulated during embryonic development. Microinjection of the mlc2f promoter-driven red fluorescent protein (RFP) reporter construct successfully exhibited heterologous expression of the fluorescent reporter, primarily in muscular areas of hatchlings, although the distribution pattern of RFP signals was not uniform due to the mosaic nature of the introduced transgene. Data from this study indicate that the Javanese ricefish mlc2f gene has undergone "intra-intronic" duplication events in a species-specific manner and that the mlc2f regulator may also be useful in heterologous expression assays of the skeletal muscles of this species.

Plastid genome of Aster altaicus var. uchiyamae Kitam., an endanger species of Korean asterids

  • Park, Jihye;Shim, Jaekyung;Won, Hyosig;Lee, Jungho
    • Journal of Species Research
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    • v.6 no.1
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    • pp.76-90
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    • 2017
  • Aster altaicus var. uchiyamae Kitam. is an endemic taxon of Korea and is protected by law as an endanger taxon. The genetic information of A. altaicus var. uchiyamae is unavailable in Genbank. Here we sequenced chloroplast genome of A. altaicus var. uchiyamae. The cp-genome of Aster altaicus var. uchiyamae was 152,446 bps in size: LSC was 84,240 bps, IR 25,005 bps, SSC 18,196 bps. The cp-genome contains 112 genes and 21 introns consisted of 79 protein coding genes(PCGs), 4 RNA genes, and 29 tRNA genes, with 20 group II introns and one group I intron. There were three pseudo-genes including ${\psi}$-ycf1, ${\psi}$-rps19, and ${\psi}$-trnT_GGU. Eighteen genes, five introns, and parts of two genes and an intron are found within the IR, which has two copies. The cp-DNA of Aster altaicus var. uchiyamae is distinguished from A. spathulifolius, only known cp-genome of the genus Aster, by 172 SNP in genic regions of 43 PCGs and 21 indels in 11 PCGs and SSU. The chloroplast genome sequence was deposited at GenBank (KX35265).