• BMB Reports
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• 제50권5호
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• pp.235-236
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• 2017

The circadian clock is an internal system that is synchronized by external stimuli, such as light and temperature, and influences various physiological and developmental processes in living organisms. In the model plant Arabidopsis, transcriptional, translational and post-translational processes are interlocked by feedback loops among morning- and evening-phased genes. In a post-translational loop, plant-specific single-gene encoded GIGANTEA (GI) stabilize the F-box protein ZEITLUPE (ZTL), driving the targeted-proteasomal degradation of TIMING OF CAB EXPRESSION 1 (TOC1) and PSEUDO-RESPONSE REGULATOR 5 (PRR5). Inherent to this, we demonstrate the novel biochemical function of GI as a chaperone and/or co-chaperone of Heat-Shock Protein 90 (HSP90). GI prevents ZTL degradation as a chaperone and facilitates ZTL maturation together with HSP90/HSP70, enhancing ZTL activity in vitro and in planta. GI is known to be involved in a wide range of physiology and development as well as abiotic stress responses in plants, but it could also interact with diverse client proteins to increase protein maturation. Our results provide evidence that GI helps proteostasis of ZTL by acting as a chaperone and a co-chaperone of HSP90 for proper functioning of the Arabidopsis circadian clock.

• Molecules and Cells
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• 제43권3호
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• pp.276-285
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• 2020

Circadian rhythm is an endogenous oscillation of about 24-h period in many physiological processes and behaviors. This daily oscillation is maintained by the molecular clock machinery with transcriptional-translational feedback loops mediated by clock genes including Period2 (Per2) and Bmal1. Recently, it was revealed that gut microbiome exerts a significant impact on the circadian physiology and behavior of its host; however, the mechanism through which it regulates the molecular clock has remained elusive. 3-(4-hydroxyphenyl)propionic acid (4-OH-PPA) and 3-phenylpropionic acid (PPA) are major metabolites exclusively produced by Clostridium sporogenes and may function as unique chemical messengers communicating with its host. In the present study, we examined if two C. sporogenes-derived metabolites can modulate the oscillation of mammalian molecular clock. Interestingly, 4-OH-PPA and PPA increased the amplitude of both PER2 and Bmal1 oscillation in a dose-dependent manner following their administration immediately after the nadir or the peak of their rhythm. The phase of PER2 oscillation responded differently depending on the mode of administration of the metabolites. In addition, using an organotypic slice culture ex vivo, treatment with 4-OH-PPA increased the amplitude and lengthened the period of PER2 oscillation in the suprachiasmatic nucleus and other tissues. In summary, two C. sporogenes-derived metabolites are involved in the regulation of circadian oscillation of Per2 and Bmal1 clock genes in the host's peripheral and central clock machineries.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2023년도 임시총회 및 춘계학술대회
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• pp.15-15
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• 2023

The chloroplast (cp) is an autonomous plant organelle with an individual genome that codes for essential cellular functions. The architecture and gene content of the cp genome is highly conserved in angiosperms. The plastome of Corydalis belongs to the Papaveraceae family, and the genome is comprised of unusual rearrangements and gene content. Thus far, no extensive comparative studies have been carried out to understand the evolution of Corydalis chloroplast genomes. Therefore, the Corydalis platycarpa cp genome was sequenced, and wide-scale comparative studies were conducted using publicly available twenty Corydalis plastomes. Comparative analyses showed that an extensive genome rearrangement and IR expansion occurred, and these events evolved independently in the Corydalis species. In addition, the protein-coding genes accD and the ndh gene loss events occurred in the common ancestor of the Corydalis and sub-clade of the Corydalis lineage, respectively. The gene ndh lost in the Corydalis-sub clade species is distributed predominantly in the Qinghai-Tibetan plateau (QTP) region. The molecular clock analysis suggests that the divergence time of all the ndh gene lost Corydalis sub-clade species occurred in the 44.31 - 15.71 mya. These results coincide very well with the uplift of the Qinghai-Tibet Plateau in the Oligocene and Miocene periods, and maybe during this period, it probably triggered the radiation of the Corydalis species. To the best of the authors' knowledge, this is the first large-scale comparative study of Corydalis plastomes and their evolution. The present study may provide insights into the plastome architecture and the molecular evolution of Corydalis species.

• 생명과학회지
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• 제27권5호
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• pp.501-508
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• 2017

Bone morphogenetic proteins (BMPs)는 다양한 세포기능을 조절하는 중요한 사이토카인 중 하나이다. 최근 BMP와 일주기 유전자들이 연관되어 있다는 연구결과들이 보고되고 있지만 조골세포에서 일주기 유전자인 Per1의 역할은 아직 명확하지 않다. 본 연구에서는 조골세포 분화에서 Per1의 역할을 조사하였다. MC3T3-E1 세포에서 BMP2 처리에 의해 Per1 mRNA 발현과 luciferase 활성이 증가하는 것을 확인하였다. 또한 Per1 과발현 실험을 통해서 Per1 유전자가 Runx2, ALP, OC의 발현을 증가시켰으며 ascorbic acid와 ${\beta}$-glycerophosphate에 의한 ALP 염색과 석회화가 Per1 과발현에 의해 더욱 증가하는 것을 확인하였다. 이상의 결과는 일주기 리듬을 조절하는 Per1 유전자가 조골세포의 분화를 촉진하는 인자로 작용함을 시사한다.

• 수면정신생리
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• 제13권1호
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• pp.22-26
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• 2006

Circadian rhythms have been observed to be disturbed in mood disorders, especially seasonal affective disorder (SAD). Clock related gene variants also have been suggested to be associated with seasonality (seasonal variations in mood and behavior). This study tested the potential association between a length polymorphism of Period3 gene and seasonal variations in mood and behavior. 297 Korean college students were genotyped for the Period3 polymorphism and were for evaluated the seasonal variation by Seasonal Pattern Assessment Questionnaire (SPAQ). The genotype frequencies were 0.76 for 4R/4R, 0.22 for 4R/5R and 0.013 for 5R/5R. The global seasonality score was not different among Period3 gene variants (4R/4R, 4R/5R and 5R/5R) except for 'sleep length' subscore. The 5R/5R genotype showed the higher 'sleep length' subscore than others (p=0.024). The comparison between seasonals (syndromal plus subsyndromal SAD determined by SPAQ) and non-seasonals did not show any significant difference in frequencies of genotypes. These findings suggest that there is a possibility that the investigated Period3 polymorphism may play a partial role in the susceptibility of seasonal variations in a Korean population.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.192.1-192
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• 2000

No Abstract, See Full Text

• Animal cells and systems
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• 제16권1호
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• pp.27-33
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• 2012

The suprachiasmatic nucleus (SCN) of the teleost hypothalamus contains a central circadian pacemaker, which adjusts circadian rhythms within the body to environmental light-dark cycles. It has been shown that exposure to darkness during the day causes phase shifts in circadian rhythms. In this study, we examined the effect of exposure to darkness on the mRNA expression levels of two circadian clock genes, namely, $Period2$ ($Per2$) and $Cryptochrome1$ ($Cry1$), and the rate-limiting enzyme in melatonin synthesis, arylalkylamine $N$-acetyltransferase-2 (Aanat2), in the pineal gland of olive flounder, $Paralichthys$ $olivaceus$. The expression of these genes showed circadian variations and was significantly higher during the dark phase. These changes may be involved in the mechanism of dark-induced phase shifts. Furthermore, this study suggests that olive flounder may be a teleost model to investigate the localization and function of circadian oscillators.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5725-5728
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• 2012

Growing evidence shows that deregulation of the circadian clock plays an important role in the development of malignant tumors, including gliomas. However, the molecular mechanisms of gene chnages controlling circadian rhythm in glioma cells have not been explored. Using real time polymerase chain reaction and immunohistochemistry techniques, we examined the expression of two important clock genes, cry1 and cry2, in 69 gliomas. In this study, out of 69 gliomas, 38 were cry1-positive, and 51 were cry2-positive. The expression levels of cry1 and cry2 in glioma cells were significantly different from the surrounding non-glioma cells (P<0.01). The difference in the expression rate of cry1 and cry 2 in high-grade (grade III and IV) and low-grade (grade 1 and II) gliomas was non-significant (P>0.05) but there was a difference in the intensity of immunoactivity for cry 2 between high-grade gliomas and low-grade gliomas (r=-0.384, P=0.021). In this study, we found that the expression of cry1 and cry2 in glioma cells was much lower than in the surrounding non-glioma cells. Therefore, we suggest that disturbances in cry1 and cry2 expression may result in the disruption of the control of normal circadian rhythm, thus benefiting the survival of glioma cells. Differential expression of circadian clock genes in glioma and non-glioma cells may provide a molecular basis for the chemotherapy of gliomas.

• 미생물학회지
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• 제32권1호
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• pp.70-77
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• 1994

Streptomyces coelicolor를 화학적 방법으로 돌연변이시킨 결과, 유전적 교잡방법에 의해 bldA와 유사한 위치인 10시 방향으로 위치가 결정되는 변이주들을 찾아내었다. 이들의 자세한 위치를 점검한 결과 cysA를 중심으로 반시계 방향으로 떨어져 있는 group고가 시계방향으로 떨어져 있는 두가지로 나뉘었다. 반시계 방향으로 떨어져 있는 변이주들을 bldA와 유사한 변이주라고 생각되어 이를 확인하기 위해 정상적인 bldA 유전자가 cloning 되어 있는 phage를 이용하여 기능적인 complementation 여부를 확인하여 보았다. Complementation이 되는 것으로 미루어 보아 이 변이주들이 bldA의 allele일 가능성이 매우 높으나 이들 중 몇몇 변이주들은 기존의 bldA와 무척 다른 양상을 보였다. 즉, 고영양 배지인 $R_2$YE배지에서 왕성하게 spore를 생산하며 wild type이 생산하는 이상의 색소 생산을 보인 점이다. 이때까지 발견된 bldA 변이주들은 배지 조성에 따라 약간의 aerial mucelium을 형성하는 것이 보고되었으나 이렇게 조건에 따라서는 완전히 bld phenotype을 잃는 변이주는 보고되지 않았다. 이 색소 생산이 실지로 항생물질 유전자의 발현에 의한 것이라는 것을 xylE fusion을 이용했을 때 유전자의 전사가 일어나는 것이 확인됨으로써 증명되었다. 또 이들 bldA 유사 변이주들은 actII-ORF4가 높음 copy수로 들어있는 pasmid에 의해 act 유전자를 발현하는 것도 관찰되었다.

• Journal of Microbiology and Biotechnology
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• 제10권2호
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• pp.169-175
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• 2000

The filamentous soil bacterium Streptomyces coelicolor is known to produce four distinct antibiotics. The simultaneous global regulation for the biosynthesis of those four antibiotics was previously confirmed by absA and absB mutations that blocked all four antibiotics' biosynthesis without influencing their morphological differentiation. To study the complex regulatory cascade that controls the secondary metabolism in Streptomyces, a new abs-like mutation was characterized. namely absR, which is slightly leaky on a complete R2YE medium, yet tight on a minimal medium. A genetic analysis of the absR locus indicated that it is located at 10 o'clock on the genetic map, near the site of absA. A cloned copy of the absA gene that encoded bacterial two-component regulatory kinases did not restore antibiotic biosyntheis to the absR mutant. Accordingly, it is proposed that absR is another abs-type mutation which is less tight than the previously identified absA or absB mutations income medium conditions, and can be used to characterize another global regulatory gene for secondary metabolete formation in S. coelicolor.