• BMB Reports
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• v.49 no.7
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• pp.355-356
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• 2016

The THO/TREX complex consists of several conserved subunits and is required for mRNA export. In metazoans, THO/TREX binds a subset of mRNAs during RNA splicing, and facilitates their nuclear export. How THO/TREX selects RNA targets is, however, incompletely understood. In our recent study, we reported that THO is loaded onto Piwi-interacting RNA (piRNA) precursor transcripts independent of splicing, and facilitates convergent transcription in Drosophila ovary. The precursors are later processed into mature piRNAs, small noncoding RNAs that silence transposable elements (TEs). We observed that piRNAs originating from dual-strand clusters, where precursors are transcribed from both strands, were specifically affected by THO mutation. Analysis of THO-bound RNAs showed enrichment of dual-strand cluster transcripts. Interestingly, THO loading onto piRNA precursors was dependent on Cutoff (Cuff), which comprises the Rhino-Deadlock-Cutoff (RDC) complex that is recruited to dual-strand clusters by recognizing H3K9me3 and licenses convergent transcription from he cluster. We also found that THO mutation affected transcription from dual-strand clusters. Therefore, we concluded that THO/TREX is recruited to dual-strand piRNA clusters, independent of splicing events, via multi-protein interactions with chromatin structure. Then, it facilitates transcription likely by suppressing premature termination to ensure adequate expression of piRNA precursors.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.66-72
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• 2012

The Nup188 protein is one of the largest evolutionally conserved nucleoprins (Nups) that compose the inner ring of nuclear pore complex (NPC). The Nup184 protein, fission yeast Schizosaccharomyces pombe ortholog of Nup188p, is required for normal growth and mRNA export in nutrient-rich medium (YES). Here, we identified a carboxyl region (482 to 1628) of Nup184 protein that was enough to complement the defects of both growth and mRNA export when the ${\Delta}nup184$ knock-out mutant was grown in YES medium. This region is also required for localization of GFP-Nup184 fusion to the nuclear periphery. In addition, we found that ORF of Nup184 (predicted 1564 amino-acid protein) registered in S. pombe GeneDB (hosted by Sanger Institute, UK) is 64 amino-acid residues shorter than that predicted by our sequence data. This carboxy-terminal region is necessary for the functions of Nup184p. We further demonstrated that Nup184 protein was conjugated with SUMO in vivo.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.105-109
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• 2008

We studied on the function and localization of fission yeast Schizosaccharomyces pombe Nup97p, which is homologous to nucleoporin Nic96p in budding yeast Saccharomyces cerevisiae. There was no effect on growth and $poly(A)^{+}$ RNA distribution of cells when nup97 gene was overexpressed. However, the haploid ${\Delta}nup97::kan^{r}$ null mutants confirmed extensive $poly(A)^{+}$ RNA accumulation in the nucleus, abnormal DNA distribution, and cessation of growth when nup97 expression was repressed. We determined the subcellular localization of Nup97 tagged at the N terminus or the C terminus with GFP. Both fusions complemented growth defect of ${\Delta}nup97::kan^{r}$ null mutants. An integrated version of the nup97-GFP fusion was constructed at the nup97 locus. Nup97-GFP fusions expressed from its own promoter was localized at the nuclear periphery with a punctate appearance. These results suggest that Nup97p in fission yeast is also nucleoporin, which is involved in mRNA export.

• Fisheries and Aquatic Sciences
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• v.20 no.7
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• pp.9.1-9.13
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• 2017

Background: Metal-responsive transcription factor-1 (MTF-1) is a key transcriptional regulator playing crucial roles in metal homeostasis and cellular adaptation to diverse oxidative stresses. In order to understand cellular pathways associated with metal regulation and stress responses in Pacific abalone (Haliotis discus hannai), this study was aimed to isolate the genetic determinant of abalone MTF-1 and to examine its expression characteristics under basal and experimentally stimulated conditions. Results: The abalone MTF-1 shared conserved features in zinc-finger DNA binding domain with its orthologs; however, it represented a non-conservative shape in presumed transactivation domain region with the lack of typical motifs for nuclear export signal (NES) and Cys-cluster. Abalone MTF-1 promoter exhibited various transcription factor binding motifs that would be potentially related with metal regulation, stress responses, and development. The highest messenger RNA (mRNA) expression level of MTF-1 was observed in the testes, and MTF-1 transcripts were detected during the entire period of embryonic and early ontogenic developments. Abalone MTF-1 was found to be Cd inducible and highly modulated by heat shock treatment. Conclusion: Abalone MTF-1 possesses a non-consensus structure of activation domains and represents distinct features for its activation mechanism in response to metal overload and heat stress. The activation mechanism of abalone MTF-1 might include both indirect zinc sensing and direct de novo synthesis of transcripts. Taken together, results from this study could be a useful basis for future researches on stress physiology of this abalone species, particularly with regard to heavy metal detoxification and thermal adaptation.

• Korean Journal of Plant Resources
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• v.31 no.3
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• pp.218-227
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• 2018

In this study, we investigated the effect of the extracts from Vaccinium oldhamii on cell proliferation and the regulatory mechanisms of cyclin D1 protein level in human cancer cells. The branch extracts from Vaccinium oldhamii (VOB) showed higher inhibitor effect against the cell growth than leave extracts (VOL) and fruit extracts (VOF) in human colorectal cancer, breast cancer, prostate cancer, non-small lung cancer, pancreatic cancer and liver cancer cells. In addition, VOB decreased cyclin D1 level at both protein and mRNA level. MG132 treatment attenuated VOB-mediated cyclin D1 downregulation. A point mutation of threonine-286 to alanine attenuated cyclin D1 degradation by VOB. In addition, the inhibition of nuclear export by leptomycin B (LMB) attenuated cyclin D1 degradation by VOB. But, the treatment of PD98059 (ERK1/2 inhibitor), SB203580 (p38 inhibitor), SP600125 (JNK inhibitor), LiCl ($GSK3{\beta}$ inhibitor), LY294002 (PI3K inhibitor) or BAY 11-7082 ($I{\kappa}K$ inhibitor) did not affect VOB-induced cyclin D1 degradation. In conclusion, VOB induced cyclin D1 degradation through redistribution of cyclin D1 from the nucleus to cytoplasm via T286 phosphorylation of cyclin D1, which resulted in the inhibition of cancer cell proliferation.