• BMB Reports
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• v.43 no.12
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• pp.789-794
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• 2010

A novel gene, designated mgt-6, containing four splicing variants, was isolated from a gene trap clone library of C3H/10T1/2 cells transfected with retroviral promoterless gene-trap vector, ROSAFARY. The transcript variants were differentially expressed in murine tissues and cell lines and differentially responded to diverse stimuli including TGF-${\beta}1$ and mitogen-activated protein kinase (MAPK) inhibitors. The mgt-6 gene encoded a protein of 37 or 11 amino acid residuals with cytoplasmic distribution. However, when C3H/10T1/2 cells were treated with 5-azacytidine, the protein translocated into cell nucleus as indicated by fused LacZ or C-terminally tagged EGFP. Our preliminary results suggest that further study on the role of mgt-6 gene in cell transformation and differentiation may be of significance.

• Journal of Periodontal and Implant Science
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• v.45 no.2
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• pp.69-75
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• 2015

Purpose: Salivary fluid formation is primarily driven by Ca2+-activated, apical efflux of chloride into the lumen of the salivary acinus. The anoctamin1 protein is an anion channel with properties resembling the endogenous calcium-activated chloride channels. In order to better understand the role of anoctamin proteins in salivary exocrine secretion, the expression of the ten members of the anoctamin gene family in the mouse submandibular gland was studied. Methods: Total RNA extracted from mouse submandibular salivary glands was reverse transcribed using primer pairs to amplify the full-length coding regions of each anoctamin gene and was subcloned into plasmid vectors for DNA sequencing. Alternative splice variants were also screened by polymerase chain reaction using primer pairs that amplified six overlapping regions of the complementary DNA of each anoctamin gene, spanning multiple exons. Results: Multiple anoctamin transcripts were found in the mouse submandibular salivary gland, including full-length transcripts of anoctamin1, anoctamin3, anoctamin4, anoctamin5, anoctamin6, anoctamin9, and anoctamin10. Exon-skipping splicing in the N-terminal exons of the anoctamins1, anoctamin5, and anoctamin6 genes resulted in multiple alternative splice variants. No expression of anoctamin2, anoctamin7, or anoctamin8 was found. Conclusions: The predominant anoctamin transcript expressed in the mouse submandibular gland is anoctamin1ac. The chloride channel protein produced by anoctamin1ac is likely responsible for the $Ca^{2+}$-activated chloride efflux, which is the rate-limiting step in salivary exocrine secretion.

• YAKHAK HOEJI
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• v.45 no.4
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• pp.426-430
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• 2001

Cells are eliminated in a variety of physiological settings by apoptosis, a genetically encoded process of cellular suicide. Bak, a member of the Bcl-2 protein family, accelerates apoptosis by an unknown mechanism. We have found a novel cDNA encoding a 101 amino acid protein possessing a Bak-like in our full-length cDNA bank. Bak-like shares the conserved domains BHI and 2 with other proapoptotic proteins but lacks the BH3 domain. Bak-like is expressed in a wide variety of tissues. Like Bak, Bak-like gene product primarily enhances apoptotic cell death following an appropriate stimulus.

• Mass Spectrometry Letters
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• v.12 no.3
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• pp.60-65
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• 2021

As a part of the Chromosome-centric Human Proteome Project (C-HPP), we have developed a few algorithms for accurate identification of missing proteins, alternative splicing variants, single amino acid variants, and characterization of function unannotated proteins. We have found missing proteins, novel and known ASVs, and SAAVs using LC-MS/MS data from human brain and olfactory epithelial tissue, where we validated their existence using synthetic peptides. According to the neXtProt database, the number of missing proteins in chromosome 11 shows a decreasing pattern. The development of genomic and transcriptomic sequencing techniques make the number of protein variants in chromosome 11 tremendously increase. We developed a web solution named as SAAvpedia for identification and function annotation of SAAVs, and the SAAV information is automatically transformed into the neXtProt web page using REST API service. For the 73 uPE1 in chromosome 11, we have studied the function annotaion of CCDC90B (NX_Q9GZT6), SMAP (NX_O00193), and C11orf52 (NX_Q96A22).

• Molecules and Cells
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• v.23 no.3
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• pp.391-397
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• 2007

FAM92A1 (named FAM92A1-271) belongs to the family of proteins with conserved DUF1208 domains. Its function remains elusive. We identified two novel transcript variants (FAM92A1-251, FAM92A1-289) of FAM92A1. The presence of these transcripts in cancerous and normal cells, as well as their influence on cell prolifera-tion and apoptosis, were investigated. The subcellular location of FAM92A1 was determined by fluorescence microscopy. We found that FAM92A1-271 and FAM92A1-289 were highly expressed in both normal and cancerous cells, but FAM92A1-251 was only expressed at a mo-derate level in both types of cell. Overexpression of FAM92A1-271, FAM92A1-251 and FAM92A1-289 inhibited cell proliferation, caused S-phase arrest and induced apoptosis. Subcellular localization showed that FAM92A1 localizes to the nucleus. Our results show that FAM92A1 has different splicing variants, and that it may take part in regulating cell proliferation and apoptosis.

• Molecules and Cells
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• v.23 no.2
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• pp.161-169
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• 2007

We identified two alternatively spliced variants of the peroxisomal targeting signal 1 (PTS1) receptor protein Pex5ps in monocot (rice, wheat, and barley) but not in dicot (Arabidopsis and tobacco) plants. We characterized the molecular and functional differences between the rice (Oryza sativa) Pex5 splicing variants OsPex5pL and OsPex5pS. There is only a single-copy of OsPEX5 in the rice genome and RT-PCR analysis points to alternative splicing of the transcripts. Putative light-responsive cis-elements were identified in the 5' region flanking OsPEX5L and Northern blot analysis demonstrated that this region affected light-dependent expression of OsPEX5 transcription. Using the pex5-deficient yeast mutant Scpex5, we showed that OsPex5pL and OsPex5pS are able to restore translocation of a model PTS1 protein (GFP-SKL) into peroxisomes. OsPex5pL and OsPex5pS formed homo-complexes via specific interaction domains, and interacted with each other and OsPex14p to form hetero-complexes. Although overexpression of OsPex5pL in the Arabidopsis pex5 mutant (Atpex5) rescued the mutant phenotype, overexpression of OsPex5pS only resulted in partial recovery.

• BMB Reports
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• v.45 no.1
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• pp.32-37
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• 2012

Alternative splicing generates several interleukin-6 (IL-6) isoforms; for them an antagonistic activity to the wild-type IL-6 has been proposed. In this study we quantified the relative abundance of IL-6 mRNA isoforms in a panel of mouse tissues and in C2C12 cells during myoblast differentiation or after treatment with the $Ca^{2+}$ ionophore A23187, the AMP-mimetic AICAR and TNF-${\alpha}$. The two mouse IL-6 isoforms identified, IL-6${\delta}$5 (deletion of the first 58 bp of exon 5) and IL-6${\delta}$3 (lacking exon 3), were not conserved in rat and human, did not exhibit tissue specific regulation, were expressed at low levels and their abundance closely correlated to that of full-length IL-6. Species-specific features of the IL-6 sequence, such as the presence of competitive 3' acceptor site in exon 5 and insertion of retrotransposable elements in intron 3, could explain the production of IL-6${\delta}$5 and IL-6${\delta}$3. Our results argued against biological significance for mouse IL-6 isoforms.

• BMB Reports
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• v.41 no.6
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• pp.415-434
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• 2008

Phosphoinositide-specific phospholipase C is an effector molecule in the signal transduction process. It generates two second messengers, inositol-1,4,5-trisphosphate and diacylglycerol from phosphatidylinositol 4,5-bisphosphate. Currently, thirteen mammal PLC isozymes have been identified, and they are divided into six groups: PLC-$\beta$, -$\gamma$, -$\delta$, -$\varepsilon$, -$\zeta$ and -$\eta$. Sequence analysis studies demonstrated that each isozyme has more than one alternative splicing variant. PLC isozymes contain the X and Y domains that are responsible for catalytic activity. Several other domains including the PH domain, the C2 domain and EF hand motifs are involved in various biological functions of PLC isozymes as signaling proteins. The distribution of PLC isozymes is tissue and organ specific. Recent studies on isolated cells and knockout mice depleted of PLC isozymes have revealed their distinct phenotypes. Given the specificity in distribution and cellular localization, it is clear that each PLC isozyme bears a unique function in the modulation of physiological responses. In this review, we discuss the structural organization, enzymatic properties and molecular diversity of PLC splicing variants and study functional and physiological roles of each isozyme.

• Molecules and Cells
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• v.27 no.4
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• pp.467-473
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• 2009

Our previous study suggested that OsBWMK1, a gene which encodes a member of the rice MAP kinase family, generates transcript variants which show distinct expression patterns in response to environmental stresses. The transcript variants are generated by alternative splicing and by use of alternative promoters. To test whether the two alternative promoters, pOsBWMK1L (promoter for the OsBWMK1L splice variant) and pOsBWMK1S (promoter for the OsBWMK1S splice variant), are biologically functional, we analyzed transgenic plants expressing GUS fusion constructs for each promoter. Both pOsBWMK1L and pOsBWMK1S are biologically active, although the activity of pOsBWMK1S is lower than that of pOsBWMK1L. Histochemical analysis revealed that pOsBWMK1L is constitutively active in most tissues at various developmental stages in rice and Arabidopsis, whereas pOsBWMK1S activity is spatially and temporally restricted. Furthermore, the expression of pOsBWMK1S::GUS was upregulated in response to hydrogen peroxide, a plant defense signaling molecule, in both plant species. These results suggest that the differential expression of OsBWMK1 splice variants is the result of alternative promoter usage and, moreover, that the mechanisms controlling OsBWMK1 gene expression are conserved in both monocot and dicot plants.

• BMB Reports
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• v.46 no.3
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• pp.163-168
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• 2013

The AML1 gene is an essential transcription factor regulating the differentiation of hematopoietic stem cells into mature blood cells. Though at least 12 different alternatively spliced AML1 mRNAs are generated, three splice variants (AML1a, AML1b and AML1c) have been characterized. Here, using the reverse transcription-polymerase chain reaction with outward-facing primers, we identified a novel non-polyadenylated transcript from the AML1 gene, with exons 5 and 6 scrambled. The novel transcript resisted RNase R digestion, indicating it is a circular RNA structure that may originate from products of mRNA alternative splicing. The expression of the novel transcript in different cells or cell lines of human and a number of other species matched those of the canonical transcripts. The discovery provides additional evidence that circular RNA could stably exist in vivo in human, and may also help to understand the mechanism of the regulation of the AML1 gene transcription.