• Mycobiology
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• 제38권1호
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• pp.26-32
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• 2010

The cyclic AMP (cAMP) pathway plays a major role in growth, sexual differentiation, and virulence factor synthesis of pathogenic fungi. In Cryptococcus neoformans, perturbation of the cAMP pathway, such as a deletion in the gene encoding adenylyl cyclase (CAC1), causes defects in the production of virulence factors, including capsule and melanin production, as well as mating. Previously, we performed a comparative transcriptome analysis of the Ras- and cAMP- pathway mutants, which revealed 163 potential cAMP-regulated genes (38 genes at a 2-fold cutoff). The present study characterized the role of one of the cAMP pathway-dependent genes (serotype A identification number CNAG_ 06576.2). The expression patterns were confirmed by Northern blot analysis and the gene was designated cAMP-regulated gene 1 (CAR1). Interestingly, deletion of CAR1 did not affect biosynthesis of any virulence factors and the mating process, unlike the cAMP-signaling deficient cac1$\Delta$ mutant. Furthermore, the car1$\Delta$ mutant exhibited wild-type levels of the stress-response phenotype against diverse environmental cues, indicating that Car1, albeit regulated by the cAMP-pathway, is not essential to confer a cAMP-dependent phenotype in C. neoformans.

• BMB Reports
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• 제32권1호
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• pp.6-11
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• 1999

To understand the function of phospholipids and their fatty acid composition on the morphological changes in the amp 1-4 mutant of Arabidopsis, the mutant was compared to the wild-type Arabidopsis by TLC, HPTLC, phosphorous assay, HPLC, and GC. In the mutant, phosphatidylethanolamine (PE) was increased 5-fold and phosphatidylglycerol (PG) was decreased 1.2-fold (nmol phosphorous/g tissue). Inositol phospholipids showed a generally increased trend ranging from 1.4-to 3.0-fold (nmol inositol/g tissue). When fatty acid composition of the mutant was compared to the wild-type, linoleic (18:2) and linolenic (18:3) acids of phosphatidylcholine (PC) and PG were decreased but palmitoleic acid (16:1) and oleic acid (18:1) of PC was increased 2.5- and 2.1-fold (mol%), respectively. In galactolipids, myristic acid (14:0) of monogalactosyl-diacylglycerol (MGDG) were increased 5.8-fold (mol%). Among the inositol phospholipids, lysophosphatidylinositol (L-PI) and phosphatidylinositol 4,5-bisphosphate ($PIP_2$) showed 4-and 1.9-fold (mol%) increase of 16:1, respectively. These results suggest that the increase of PE, the decrease of PG, the increase of inositol phospholipids, and the altered fatty acid composition are related to the phenotypic changes affecting the morphological features, and might cause different physiological changes in the amp 1-4 mutant compared to wild-type Arabidopsis.

• 한국동물생명공학회지
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• 제34권4호
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• pp.267-271
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• 2019

This study aimed to investigate the function of the constitutively activating mutation D540G on eel FSHR activity by in vitro functional studies. Site-directed mutagenesis was carried out to generate the D-to-G mutation at position 540 of the pcDNA3-eel FSHR construct. Vectors expressing either wild type or mutant receptor were transfected into Chinese hamster ovary (CHO-K1) cells. The functional characteristics of both the wild type and mutant receptors were analyzed by a cAMP assay. cAMP accumulation was highly increased in cells transfected with the D540G mutant receptor in a dose-dependent manner. Of note, basal cAMP levels were remarkably increased (~13.1-fold) with expression of this mutant when compared to wild type receptor. These findings suggest that the D540G mutation in the eel FSHR may contribute to ovulation during eel sex maturation as well as play a pivotal role in inducing FSHR activity.

• Animal cells and systems
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• 제10권4호
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• pp.237-241
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• 2006

Chemotactic behavior is essential for the survival of animals. However, the mechanism by which animals carry out chemotaxis is poorly understood. To explore the biochemical events underlying chemotaxis, we isolated C. elegans mutants that displayed abnormal chemotactic responses to cAMP, a strong attractant for C. elegans. Based on their responses to other chemoattractants, the mutant animals could be classified into five groups: (1) animals with defective chemotaxis to cAMP only; (2) animals with defective chemotaxis to both cAMP and cGMP; (3) animals with defective chemotaxis to water-soluble attractants; (4) animals with defective chemotaxis to both water-soluble and volatile attractants; and (5) animals with enhanced chemotactic responses. We expect that analyses of these mutants will help understand the molecular mechanisms underlying chemotaxis in C. elegans.

• Journal of Microbiology and Biotechnology
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• 제19권6호
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• pp.542-546
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• 2009

Leaves are the major biomass-producing organs in herbaceous plants and mainly develop during vegetative stage by activities of shoot apical meristem. There is a strong correlation between leaf number and bolting, a characteristic phenotype during the transition to reproductive phase in Arabidopsis thaliana. In order to study interactions between leaf number and bolting, we isolated a Landsberg erecta-derived mutant named multifolial (mfo1) that produces increased number of leaves and bolts at the same time as the wild type. Through positional cloning and allelism test, mfo1 was found to be an allele of a previously reported mutant, altered meristem program1-1 (amp1-1) that is defective in a glutamate carboxypeptidase and bolts earlier than its wild type, Columbia ecotype, with the increased number of leaves. The bolting time differences between mfo1 and amp1, despite the same phenotype of many leaves, suggest the existence of genetic factor(s) differently function in each ecotype in the presence of mfo1/amp1 mutation.

• 한국가축번식학회지
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• 제24권1호
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• pp.41-47
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• 2000

성선자극호르몬 수용체 (LH/CGR)는 7번 막을 통과하는 수용체의 일종이다. LH/CGR의 유전자 돌연변이 질환은 남성에 있어서 이들 수용체가 조기에 발현되어 조기 성숙의 원인이 된다. 이러한 수용체의 기능을 분석하기 위하여 556번째의 아미노산 (D)을 Y로 치환한 돌연변이 수용체 (D556Y)를 만들었다. 이러한 돌연변이 수용체를 동물세포에 발현시켜 cAMP의 분석결과 Ligand (호르몬)가 없어도 지속적으로 정보전달을 세포내부로 보내 cAMP 발현을 현저히 증가시켰다. 따라서 남성의 조기성숙과 관련된 질환은 지속적으로 발현하는 LH /CGR에 의한 원인 때문일 것이다.

• Bulletin of the Korean Chemical Society
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• 제19권11호
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• pp.1202-1206
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• 1998

We have explored the impact of altering the Ras-cAMP pathway on cell survival upon oxidative exposures. A hyperactivated Ras mutant of Saccharomyces cerevisiae, intrinsically more sensitive to heat shock than the wild type, was investigated with regard to oxidative stress. In this paper we report that the response of iral, ira2-deleted mutant (IR2.53) to an oxidant, such as hydrogen peroxide (H2O2) or menadione is more sensitive than that of the wild type. IR2.53 showed a dramatic decrease in survival rate when challenged with 0.1 mM H2O2 for 30 min. The greater sensitivity of IR2.53 was also noticed with treatment of 0.01 mM menadione. Prior to oxidative stresses by these oxidants, both the wild type and the mutant were preconditioned with a mild heat shock (37 ℃, 30 min), resulting in improved survivals against oxidative stresses. Rescue of IR2.53 from menadione stress by heat pretreatment was more clearly demonstrated than that from H2O2 treatment. On the other hand, no significant difference was observed between the wild type and the IR2.53 mutant in their survival rates upon paraquat treatments. These findings imply that the mechanism by which H2O2 and menadione put forth their oxidative effects may be closely associated with the cAMP-Ras pathway whereas that of paraquat is independent of the Ras pathway. Finally, the level of glutathione (GSH) was measured enzymatically as an indicator of antioxidation and compared with the survival rate. Taken all these together, this study provides an insight into a mechanism of the Ras pathway regulated by several oxidants and suggests that the Ras pathway plays a crucial role in protection of cell damage following oxidative stress.

• 한국초지조사료학회지
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• 제27권4호
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• pp.241-248
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• 2007

Cytokinin은 식물의 성장과 발달에 중요한 역할을 하는 필수 호르몬이다. mRNA differential display 방법으로 애기장대 amp1 돌연변이체로부터 cytokinin에 의하여 발현이 유도되는 PR4 유전자를 분리하였다. AtPR4로 명명한 애기장대 PR4 유전자는 212개의 아미노산으로 구성되어 있었으며 분자량은 22,900이고 등전점은 7.89로 추정되었다. Genomic DNA 분석결과, AtPR4는 single copy 유전자인 것으로 나타났다. AtPR4의 mRNA는 cytokinin과 NaCl에 의해서는 발현이 유도되었지만 SA와 JA에 의해서는 발현이 억제되었다. PR 단백질은 내병성 등 생체방어기작에 관여하는 것으로 알려져 있다. 따라서 본 연구에서 분리한 애기장대 PR4 유전자는 내병성 목초 품종의 개발에 유용하게 사용될 것으로 사료된다.

• 한국균학회지
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• 제21권4호
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• pp.285-292
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• 1993

에너지 요구 반응 인 5'-XMP 의 5'-GMP 보의 효소적 전환을 위해 Escherichia coli CH 41(guaB mutant)로부터 추출 정제한 XMP aminase에 Saccharomyces cerevisiae의 glycolysis를 통한 ATP 재생계를 도입하였다. 전환 반응의 ATP원으로는 동결 건조 효모가 가장 효율적이었으며, 전환 반응의 최적 온도 및 pH는 각각 $40{\circ]C$, pH 7.4였다. 또한 100 mM glucose, 100 mM inorganic phosphate 및 6mM AMP 에서 가상 높은 전환율을 보였다. 상기의 조건에서 36 unit/ml의 XMP aminase 가 이용될 경우 효모 농도는 60 mg/ml로 충분하였으며, 최적 조건에서 6시간 반응시 1.8 mM(65.6 mg/100 ml) 5'- XMP 의 약 71%가 5'-GMP로 전환되었다.

• 한국발생생물학회지:발생과생식
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• 제25권3호
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• pp.133-143
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• 2021

In contrast to the human lutropin receptor (hLHR) and rat LHR (rLHR), very few naturally occurring mutants in other mammalian species have been identified. The present study aimed to delineate the mechanism of signal transduction by three constitutively activating mutants (designated M410T, L469R, and D590Y) and two inactivating mutants (D383N and Y546F) of the eel LHR, known to be naturally occurring in human LHR transmembrane domains. The mutants were constructed and measured cyclic adenosine monophosphate (cAMP) accumulation via homogeneous time-resolved fluorescence assays in Chinese hamster ovary (CHO)-K1 cells. The activating mutant cells expressing eel LHR-M410T, L469R, and D590Y exhibited a 4.0-, 19.1-, and 7.8-fold increase in basal cAMP response without agonist treatment, respectively. However, inactivating mutant cells expressing D417N and Y558F did not completely impaired signal transduction. Specifically, signal transduction in the cells expressing activating mutant L469R was not occurred with a further ligand stimulation, showing that the maximal response exhibited approximately 53% of those of wild type receptor. Our results suggested that the constitutively activating mutants of the eel LHR consistently occurred without agonist treatment. These results provide important information of LHR function in fish and regulation with regard to mutations of highly conserved amino acids in glycoprotein hormone receptors.