• BMB Reports
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• 제56권9호
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• pp.514-519
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• 2023

Methyltransferase-like 3 (METTL3), a key component of the m⁶A methyltransferase complex, regulates the splicing, nuclear transport, stability, and translation of its target genes. However, the mechanism underlying the regulation of METTL3 expression by alternative splicing (AS) remains unknown. We analyzed the expression pattern of METTL3 after AS in human tissues and confirmed the expression of an isoform retaining introns 8 and 9 (METTL3-IR). We confirmed the different intracellular localizations of METTL3-IR and METTL3 proteins using immunofluorescence microscopy. Furthermore, the endogenous expression of METTL3-IR at the protein level was different from that at the mRNA level. We found that 3'-UTR generation by intron retention (IR) inhibited the export of METTL3-IR mRNA to the cytoplasm, which in turn suppressed protein expression. To the best of our knowledge, this is the first study to confirm the regulation of METTL3 gene expression by AS, providing evidence that the suppression of METTL3 protein expression by IR is an integral part of the mechanism by which 3'-UTR generation regulates protein expression via inhibition of RNA export to the cytoplasm.

• Journal of Genetic Medicine
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• 제20권2호
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• pp.39-45
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• 2023

As advanced sequencing technologies continue to uncover an increasing number of variants in genes associated with human genetic diseases, there is a growing demand for systematic approaches to assess the impact of these variants on human development, health, and disease. While in silico analyses have provided valuable insights, it is essential to complement these findings with model organism studies to determine the functional consequences of genetic variants in vivo. Drosophila melanogaster is an excellent genetic model for such functional studies due to its efficient genetic technologies, high gene conservation with humans, accessibility to mutant fly resources, short life cycles, and cost-effectiveness. The traditional GAL4-UAS system, allowing precise control of gene expression through binary regulation, is frequently employed to assess the effects of monoallelic variants. Recombinase medicated cassette exchange or CRISPR-Cas9-mediated GAL4 insertion within coding introns or substitution of gene body with Kozak-Gal4 result in the loss-of-function of the target gene. This GAL4 insertion strategy also enables the expression of reference complementary DNA (cDNA) or cDNA carrying genetic variants under the control of endogenous regulatory cis elements. Furthermore, the CRISPR-Cas9-directed tissue-specific knockout and cDNA rescue system provides the flexibility to investigate candidate variants in a tissue-specific and/or developmental-timing dependent manner. In this review, we will delve into the diverse genetic techniques available in Drosophila and their applications in diagnosing and studying numerous undiagnosed diseases over the past decade.

• BMB Reports
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• 제40권5호
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• pp.791-800
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• 2007

Ethylene performs an important function in plant growth and development. 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS), the key enzyme involved in ethylene biosynthesis, has been the focus of most ethylene studies. Here, a cotton ACS gene referred to as Gossypium hirsutum ACS1 (GhACS1), was isolated. The full-length cDNA of GhACS1 encodes for a 476-amino acid protein which harbors seven conserved regions, 11 invariant amino acid residues, and the PLP binding active site, all of which characterize ACC synthases. Alignment analysis showed that GhACS1 shared a high degree of identity with other known ACC synthases from different species. Two introns were detected in the genomic DNA sequence, and the results of Southern blot analysis suggested that there might be a multi-gene family encoding for ACC synthase in cotton. From the phylogenetic tree constructed with 24 different kinds of ACC synthases, we determined that GhACS1 falls into group II, and was closely associated with the wound-inducible ACS of citrus. The analysis of the 5' flanking region of GhACS1 revealed a group of putative cis-acting elements. The results of expression analysis showed that GhACS1 displayed its transient expression nature after wounding, abscisic acid (ABA), and $CuCl_2$ treatments. These results indicate that GhACS1, which was transiently expressed in response to certain stimuli, may be involved in the production of ethylene for the transmission of stress signals.

• Molecules and Cells
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• 제27권5호
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• pp.539-546
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• 2009

In Saccharomyces cerevisiae, ribosomal protein L7, one of the ~46 ribosomal proteins of the 60S subunit, is encoded by paralogous RPL7A and RPL7B genes. The amino acid sequence identity between RPl7a and RPl7b is 97 percent; they differ by only 5 amino acid residues. Interestingly, despite the high sequence homology, Rpl7b is detected in both the cytoplasm and the nucleolus, whereas Rpl7a is detected exclusively in the cytoplasm. A site-directed mutagenesis experiment revealed that the change in the amino acid sequence of Rpl7b does not influence its subcellular localization. In addition, introns of RPL7A and RPL7B did not affect the subcellular localization of Rpl7a and Rpl7b. Remarkably, Rpl7b was detected exclusively in the cytoplasm in rpl7a knockout mutant, and overexpression of Rpl7a resulted in its accumulation in the nucleolus, indicating that the subcellular localization of Rpl7a and Rpl7b is influenced by the intracellular level of Rpl7a. Rpl7b showed a wide range of localization patterns, from exclusively cytoplasmic to exclusively nucleolar, in knockout mutants for some rRNA-processing factors, nuclear pore proteins, and large ribosomal subunit assembly factors. Rpl7a, however, was detected exclusively in the cytoplasm in these mutants. Taken together, these results suggest that although Rpl7a and Rpl7b are paralogous and functionally replaceable with each other, their precise physiological roles may not be identical.

• 한국자원식물학회지
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• 제26권3호
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• pp.397-402
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• 2013

Morus Folium (Sang-yeop in Korean) is one of the most important Oriental medicinal plants. In Korea, both M. alba and M. cathayana are regarded as the botanical sources for Morus Folium. In order to discriminate M. alba and M. cathayana from their adulterant, M. tricuspidata, mitochondrial NADH dehydrogenase subunit 7 (nad7) intron 2 region was targeted for molecular analysis with universal primers. DNA polymorphisms, including SNP sites, insertions, and deletions, were detected among these three species sequencing data. Based on these DNA polymorphisms, specific primers were designed for the three species respectively. Multiplex PCR was conducted for molecular authentication of M. alba, M. cathayana, and M. tricuspidata with specific primers. The present results indicate that it is possible to identify Morus Folium from its adulterant using mitochondrial nad7 intron 2 region. The established multiplex-PCR system was proved to be effective for identification of Morus Folium. The results indicate that mitochondrial introns can be used for inter-specific polymorphic study, and the described method can be applied for molecular identification of medicinal materials.

• Asian-Australasian Journal of Animal Sciences
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• 제21권8호
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• pp.1073-1079
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• 2008

The objectives of this study were to identify polymorphisms of insulin-like growth factor I (IGF-I) gene and to investigate their association with growth traits in Nanjiang Huang goats. Five hundred and ninety-two animals were used to detect the polymorphisms in the complete coding sequence, part of introns and the 5'-regulatory region of the IGF-I gene by means of PCR-SSCP. A new single nucleotide polymorphism (G to C transversion) was identified at intron 4 of the IGF-I gene in the goats. Two alleles and three genotypes were observed in this group. The frequency of G and C alleles was 54.6 and 45.4%, respectively. The statistical analysis showed that polymorphism of the IGF-I gene had a significant association (p<0.05) with birth weight (BW), body weight at 6 months (W6) and at 12 months (W12), heart girth at 2 months (G2), body length at 6 months (L6), wither height at 6 months (H6) and at 12 months (H12) and heart girth at 12 months (G12). The goats with genotype CC had significantly higher BW, W6, W12, G2, L6, H6, H12 and G12 than those with genotype GC and had significantly higher W12, H6, H12 and G12 than those with genotype GG. Therefore, genotype CC may be the most advantageous for growth traits in the Nanjiang Huang goat. However, no significant association between SNP genotypes and other growth traits was observed. These results indicated that the SNP marker of the IGF-I gene may be a potential molecular marker for growth traits in Nanjiang Huang goats.

• BMB Reports
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• 제40권4호
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• pp.577-587
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• 2007

Single-copy chloroplast loci are used widely to infer phylogenetic relationship at different taxonomic levels among various groups of plants. To test the utility of chloroplast loci and to provide additional data applicable to hybrid evolution in Musa, we sequenced two introns, rpl16 and ndhA, and two intergenic spacers, psaA-ycf3 and petA-psbJ-psbL-psbF and combined these data. Using these four regions, Musa acuminata Cola(A)- and M. balbisiana Colla (B)-containing genomes were clearly distinguished. Some triploid interspecific hybrids contain A-type chloroplasts (the AAB/ABB) while others contain B-type chloroplasts (the BBA/BBB). The chloroplasts of all cultivars in 'Namwa' (BBA) group came from the same wild maternal origin, but the specific parents are still unrevealed. Though, average sequence divergences in each region were little (less than 2%), we propose that petA-psbJ intergenic spacer could be developed for diversity assessment within each genome. This segment contains three single nucleotide polymorphisms (SNPs) and two indels which could distinguish diversity within A genome whereas this same region also contains one SNP and an indel which could categorize B genome. However, an inverted repeat region which could form hairpin structure was detected in this spacer and thus was omitted from the analyses due to their incongruence to other regions. Until thoroughly identified in other members of Musaceae and Zingiberales clade, utility of this inverted repeat as phylogenetic marker in these taxa are cautioned.

• Molecules and Cells
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• 제25권1호
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• pp.112-118
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• 2008

Laccases are multicopper-containing oxidases that catalyze the oxidation of many aromatic compounds with concomitant reduction of oxygen to water. Interest in this enzyme has arisen in many fields of industry, including detoxification, wine stabilization, paper processing, and enzymatic conversion of chemical intermediates. In this study, we cloned a laccase gene (GLlac1) from the white-rot fungus Ganoderma lucidum. The cloned gene consists of 4,357 bp, with its coding region interrupted by nine introns, and the upstream region has putative CAAT and TATA boxes as well as several metal responsive elements (MREs). We also cloned a full-length cDNA of GLlac1, which contains an uninterrupted open reading frame (ORF) of 1,560 bp coding for 520 amino acids with a putative 21-residue signal sequence. The DNA and deduced amino acid sequences of GLlac1 were similar but not identical to those of other fungal laccases. GLlac1 was released from the cells when expressed in P. pastoris, and had high laccase activity. In addition, GLlac1 conferred antioxidative protection from protein degradation, and thus may be useful in bio-medical applications.

• 대한의생명과학회지
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• 제14권1호
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• pp.47-53
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• 2008

Hox genes are known to be transcription factors controlling vertebrate pattern formation along the anteroposterior body axis by regulating many target gene expressions during vertebrate embryogenesis. In order to isolate in vivo Hox responsive target genes, ChIP-cloning technique has been applied using Hoxc8 antibody. Here murine embryo of day 11.5 post coitum (E11.5) highly expressing Hoxc8 gene was used after removing head and tail portions where Hoxc8 is rarely expressing. After fixation with formaldehyde, the chromatin DNAs harboring bound proteins were isolated. After sonication, about 0.5- to 1 Kb chromatin DNAs were immunoprecipitated with anti Hoxc8 antibody. After removing the bound proteins with proteinase K, DNAs were isolated, cloned into the pBluescsript II SK vector, and then sequenced. Total 33 random clones sequenced were anlalyzed to be located at 12 different genomic regions. Among these, 8 turned out to be introns and 4 were intergenic regions localized in random chromosomes. The base composition of total cloned genomic sequences (6608 bp) were AT-rich, i.e., 40% GC. When the Hoxc8 core binding sites, such as TAAT, ATTA, TTAT, and ATAA were analyzed total number of 55, 45, 54, and 55 were found, respectively, which are than twice as many as expected number of 26. Although this in silico analysis does not mean that the ChIP-cloned sequence is real Hoxc8 regulatory element in vivo, these results strongly imply that the DNA fragments cloned through chromatin immunoprecipitation could be very much likely the putative Hoxc8 downstream target genes.

• Asian-Australasian Journal of Animal Sciences
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• 제23권7호
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• pp.855-862
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• 2010

Among the known interferon-induced antiviral mechanisms, the Mx pathway is one of the most powerful pathways. The Mx protein has direct antiviral activity and inhibits a wide range of viruses by blocking an early stage of the viral replication cycle. Cloning, characterization, and expression of Mx in vivo and in vitro have been conducted. The chicken Mx gene spans 21 kb and is made up of 14 exons and 13 introns, of which the promoter region was analyzed. The real-time PCR results showed that Mx expression was increased in chicken embryo fibroblasts (CEF) after 12- and 24-h induction with polyI: C. Induction of Mx expression by poly I: C in vivo revealed tissue-specific patterns among the chicken tissues tested. A trace expression of Mx was detected in healthy chicken liver tissues from adult chickens without inducement; the expression levels in the liver, heart, and gizzard were higher than in the muscle and kidney. This is the first report to demonstrate the expression of a glutathione-S-transferase-tagged-Mx fusion protein of 75 KDa, as well as the biological activity tested by SDS-PAGE and western blotting.