• Molecules and Cells
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• 제38권8호
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• pp.723-728
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• 2015

Smurf2, a member of the HECT domain E3 ligase family, is well known for its role as a negative regulator of TGF-${\beta}$ signaling by targeting Smads and TGF-${\beta}$ receptor. However, the regulatory mechanism of Smurf2 has not been elucidated. Arginine methylation is a type of post-translational modification that produces monomethylated or dimethylated arginine residues. In this report, we demonstrated methylation of Smurf2 by PRMT1. In vitro methylation assay showed that Smurf2, not Smurf1, was methylated by PRMT1. Among the type I PRMT family, only PRMT1 showed activity for Smurf2. Transiently expressed Smurf2 was methylated by PRMT1, indicating Smurf2 is a novel substrate of PRMT1. Using deletion constructs, methylation sites were shown to be located within amino acid region 224-298 of Smurf2. In vitro methylation assay following point mutation of putative methylation sites confirmed the presence of Arg232, Arg234, Arg237, and Arg239. Knockdown of PRMT1 resulted in increased Smurf2 expression as well as inhibition of TGF-${\beta}$-mediated reporter activity. Although it is unclear whether or not increased Smurf2 expression can be directly attributed to lack of methylation of arginine residues, our results suggest that methylation by PRMT1 may regulate Smurf2 stability and control TGF-${\beta}$ signaling.

• Molecules and Cells
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• 제22권2호
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• pp.146-153
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• 2006

Cell polarity is critical for the division, differentiation, migration, and signaling of eukaryotic cells. RAX2 of budding yeast encodes a membrane protein localized at the cell cortex that helps maintain the polarity of the bipolar pattern. Here, we designate SPAC6f6.06c as $rax2^+$ of Schizosaccharomyces pombe, based on its sequence homology with RAX2, and examine its function in cell polarity. S. pombe $rax2^+$ is not essential, but ${\Delta}rax2$ cells are slightly smaller and grow slower than wild type cells. During vegetative growth or arrest at G1 by mutation of cdc10, deletion of $rax2^+$ increases the number of cells failing old end growth just after division. In addition, this failure of old end growth is dramatically increased in ${\Delta}tea1{\Delta}rax2$, pointing to genetic interaction of $rax2^+$ with $tea1^+$. ${\Delta}rax2$ cells contain normal actin and microtubule cytoskeletons, but lack actin cables, and the polarity factor for3p is not properly localized at the growing tip. In ${\Delta}rax2$ cells, and endogenous rax2p is localized at the cell cortex of growing cell tips in an actin- and microtubule-dependent manner. However, ${\Delta}rax2$ cells show no defects in cell polarity during shmoo formation and conjugation. Taken together, these observations suggest that rax2p controls the cell polarity of fission yeast during vegetative growth by regulating for3p localization.

• 환경생물
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• 제20권4호
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• pp.316-324
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• 2002

To investigate the mutational spectrum of laccase (Lac) genes (lac -A and lac -B) involved in degrading lignin which is the recalcitrant cell wall polymer, the genes of the Pleurotus ostreatus mutants induced by gamma ray radiation were amplified by PCR and were cloned. All partial lac-A genes of 4 mutants (PO-6, -7, -14 and -15) consisted of 1763 base pairs due to the deletion of two bases (491-nt and 492-nt) and addition of one base (875-nt) in 1764 base pairs of lac -A gene of PO-1. Totally 36 mutational hot spots were detected and 32 positions were mutated in all of those 4 mutants simultaneously. These mutations were predominantly A : T -> G : C transitions (40%). Putative amino acid sequences of lac -A genes of mutants have one simultaneous mutated residue (from Thr-44 to Ala-44). The 1764 bp of partial lac -B gene was cloned only in PO -5 mutant and contained 19 mutated bases. These mutations were predominantly G : C->A : T transitions (45%). Lac-B protein of PO-5 has two mutated residues of Glu-290 and His-363 from Ala-290 and Phe-363, respectively. The hyper-mutational positions were concentrated in specific regions of between 50-nt and 900-nt in lac genes. These results suggested that the mutational hotspots responded to gamma radiation could be in some genes, at least lac -A and lac -B of p. ostreatus.

• 한국수정란이식학회지
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• 제30권4호
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• pp.299-303
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• 2015

KO mice provide an excellent tool to determine roles of specific genes in biomedical filed. Traditionally, knockout mice were generated by homologous recombination in embryonic stem cells. Recently, engineered nucleases, such as zinc finger nuclease, transcription activator-like effector nuclease and clustered regularly interspaced short palindromic repeats (CRISPR), were used to produce knockout mice. This new technology is useful because of high efficiency and ability to generate biallelic mutation in founder mice. Until now, most of knockout mice produced using engineered nucleases were C57BL/6 strain. In the present study we used CRISPR-Cas9 system to generate knockout mice in FVB strain. We designed and synthesized single guide RNA (sgRNA) of CRISPR system for targeting gene, Abtb2. Mouse zygote were obtained from superovulated FVB female mice at 8-10 weeks of age. The sgRNA was injected into pronuclear of the mouse zygote with recombinant Cas9 protein. The microinjected zygotes were cultured for an additional day and only cleaved embryos were selected. The selected embryos were surgically transferred to oviduct of surrogate mother and offsprings were obtained. Genomic DNA were isolated from the offsprings and the target sequence was amplified using PCR. In T7E1 assay, 46.7% among the offsprings were founded as mutants. The PCR products were purified and sequences were analyzed. Most of the mutations were founded as deletion of few sequences at the target site, however, not identical among the each offspring. In conclusion, we found that CRISPR system is very efficient to generate knockout mice in FVB strain.

• 한국수정란이식학회지
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• 제29권4호
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• pp.339-344
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• 2014

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein (Cas9) system can be applied to produce transgenic pigs. Therefore, we applied CRISPR/Cas9 system to generate FoxN1-targeted pig parthenogenetic embryos. Using single guided RNA targeted to pig FoxN1 genes was injected into cytoplasm of in vitro matured oocyte before electrical activation. In results, regardless of the concentrations of vector, the cleavage rate were significantly (p<0.05) decreased ($4ng/{\mu}l$, 51.24%; $8ng/{\mu}l$, 40.88%; and $16ng/{\mu}l$; 45.22%) compared to no injection group (70.44%). The blastocyst formation rates were also decreased in vector injected 3 groups ($4ng/{\mu}l$, 7.96%; $8ng/{\mu}l$, 6.4%; and $16ng/{\mu}l$; 9.04%) compared to no injection group (29.07%). In addition, the blastocyst formation rates between sham injected group (13.51%) and no injection group (29.07%) also showed significant difference (p<0.05). The mutation rates were comparable between groups ($4ng/{\mu}l$, 18.4%; $8ng/{\mu}l$, 12.5%; and $16ng/{\mu}l$; 20.0%). The sequencing analysis showed that blastocysts derived from each group were successfully mutated in FoxN1 loci regardless of the vector concentrations. However, the deletion patterns were higher than the patterns of point mutation and insertion regardless of the vector concentrations. In conclusion, we described that cytoplasmic microinjection of FoxN1-targeted CRISPR/Cas9 vector could efficiently generate transgenic pig parthenogenetic embryos in one-step.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2002년도 학술발표대회
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• pp.18-25
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• 2002

The pikromycin biosynthetic system in Streptomyces venezuleae is unique for its ability to produce two groups of antibiotics that include the 12-membered ring macrolides methymycin and neomethymycin, and the 14-membered ring macrolides narbomycin and pikromycin. The metabolic pathway also contains two post polyketide-modification enzymes, a glycosyltransferase and P450 hydroxylase that have unusually broad substrate specificities. In order to explore further the substrate flexibility of these enzymes a series of hybrid polyketide synthases were constructed and their metabolic products characterized. The plasmid-based replacement of the multifunctional protein subunits of the pikromycin PKS in S. venezuelae by the corresponding subunits from heterologous modular PKSs resulted in recombinant strains that produce both 12- and 14-membered ring macrolactones with predicted structural alterations. In all cases, novel macrolactones were produced and further modified by the DesVII glycosyltransferase and PikC hydroxylase leading to biologically active macrolide structures. These results demonstrate that hybrid PKSs in S. venezuelae can produce a multiplicity of new macrolactones that are modified further by the highly flexible DesVII glycosyltransferase and PikC hydroxylase tailoring enzymes. This work demonstrates the unique capacity of the S. venezuelae pikromycin pathway to expand the toolbox of combinatorial biosynthesis and to accelerate the creation of novel biologically active natural products. The polyketide backbone of rifamycin B is assembled through successive condensation and ${\beta}$-carbonyl processing of the extender units by the modular rifamycin PKS. The eighth module, in the RifD protein, contains nonfunctional DH domain and functional KR domain, which specify the reduction of the ${\beta}$-carbonyl group resulting in the C-21 bydroxyl of rifamycin B. A four amino acid substitution and one amino acid deletion were introduced in the putative NADPH binding motif in the proposed KR domain encoded by rifD. This strategy of mutation was based on the amino acid sequences of the corresponding motif of the KR domain of module 3 in the RifA protein, which is believed dysfunctional, so as to introduce a minimum alteration and retain the reading frame intact, yet ensure loss of function. The resulting strain produces linear polyketides, from tetraketide to octaketide, which are also produced by a rifD disrupted mutant as a consequence of premature termination of polyketide assembly. Much of the structural diversity within the polyketide superfamily of natural products is due to the ability of PKSs to vary the reduction level of every other alternate carbon atom in the backbone. Thus, the ability to introduce heterologous reductive segments such as ketoreductase (KR), dehydratase (DH), and enoylreductase (ER) into modules that naturally lack these activities would increase the power of the combinatorial biosynthetic toolbox. The dehydratase domain of module 7 of the rifamycin PKS, which is predicted to be nonfunctional in view of the sequence of the apparent active site, was replaced with its functional homolog from module 7 of rapamycin-producing polyketide synthase. The resulting mutant strain behaved like a rifC disrupted mutant, i.e., it accumulated the heptaketide intermediate and its precursors. This result points out a major difficulty we have encountered with all the Amycolatopsis mediterranei strain containing hybrid polyketide synthases: all the engineered strains prepared so far accumulate a plethora of products derived from the polyketide chain assembly intermediates as major products instead of just analogs of rifamycin B or its ansamycin precursors.

• BMB Reports
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• 제53권6호
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• pp.323-328
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• 2020

Matrix metalloproteinase 1 (MMP-1), a calcium-dependent zinccontaining collagenase, is involved in the initial degradation of native fibrillar collagen. Tissue necrosis factor-alpha (TNFα) is a pro-inflammatory cytokine that is rapidly produced by dermal fibroblasts, monocytes/macrophages, and keratinocytes and regulates inflammation and damaged-tissue remodeling. MMP-1 is induced by TNFα and plays a critical role in tissue remodeling and skin aging processes. However, the regulation of the MMP1 gene by TNFα is not fully understood. We aimed to find additional cis-acting elements involved in the regulation of TNFα-induced MMP1 gene transcription in addition to the nuclear factor-kappa B (NF-κB) and activator protein 1 (AP1) sites. Assessments of the 5'-regulatory region of the MMP1 gene, using a series of deletion constructs, revealed the requirement of the early growth response protein 1 (EGR-1)-binding sequence (EBS) in the proximal region for proper transcription by TNFα. Ectopic expression of EGR-1, a zinc-finger transcription factor that binds to G-C rich sequences, stimulated MMP1 promoter activity. The silencing of EGR-1 by RNA interference reduced TNFα-induced MMP-1 expression. EGR-1 directly binds to the proximal region and transactivates the MMP1 gene promoter. Mutation of the EBS within the MMP1 promoter abolished EGR-1-mediated MMP-1 promoter activation. These data suggest that EGR-1 is required for TNFα-induced MMP1 transcriptional activation. In addition, we found that all three MAPKs, ERK1/2, JNK, and p38 kinase, mediate TNFα-induced MMP-1 expression via EGR-1 upregulation. These results suggest that EGR-1 may represent a good target for the development of pharmaceutical agents to reduce inflammation-induced MMP-1 expression.

• Childhood Kidney Diseases
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• 제16권2호
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• pp.73-79
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• 2012

목적: 일부 사구체 질환 그리고 말기 신부전 환자를 대상으로 한 연구들에서 특정 부위의 돌연변이와 deletion 그리고 미토콘드리아 DNA copy 수 등이 예후적인 경과와 관련이 있다는 주장이 제기되었다. 연구자들은 소아 IgA 신병증 환자를 대상으로 혈소판을 이용한 미토콘드리아 DNA 전체 염기서열 분석을 실시하였다. 방법: 인제의대 부산백병원 소아청소년과에서 신생검을 실시하여 IgA 신병증으로 확진된 7명의 환자를 대상으로 하였다. 대상 환아들은 동반된 전신질환이 없고 가족력상 신장질환이 없는 경우로 국한 하였다. 신생검 당시 혈청 크레아티닌 치와 사구체 여과율은 모두에서 정상 범위였으며, 각각의 연령 대에 정상 범위의 혈압을 보였다. 환자의 성별은 남자 4명 여자 3명 이었다. 환자들은 단백뇨의 정도에 따라 두 군으로 분류하였다. 결과: 신생검 당시 환자들의 평균 나이는 $11.5{\pm}2.2$세 였으며 최종 추적검사 당시의 나이는 평균 $17.9{\pm}3.2$세 였다. 환자들의 평균 추적관찰 기간은 평균 $7.8{\pm}3.1$년 이었다. 환자들은 입원당시 단백뇨의 정도에 따라 2군으로 분류하였다. 1군은 입원당시 단백뇨가 동반되지 않았던 환자들이며 2군은 신증후군의 임상 양상을 보인 환자들이었다. 최종 추적 관찰 당시 양군의 혈청 크레아티닌 치, BUN은 모두 정상 범위였다. 혈청 알부민 치는 2군에서 $3.7{\pm}0.6g/dL$로 1군의 $4.7{\pm}0.2g/dL$에 비해 유의하게 낮았으며(P=0.0241), 혈청 콜레스테롤치는 2군에서 $222.7{\pm}35.7mg/dL$로 1군의 $148.3{\pm}29.1mg$ 보다 유의하게 높았다(P=0.0283). 24시간 채집뇨상의 총단백량도 2군에서 $1,466.0{\pm}742.5\;gm$으로 1군의 $122.5{\pm}48.1\;gm$에 비해 유의하게 높았다(P=0.0135). 단회 소변을 이용한 단백/크레아티닌 비는 2군에서 $1.8{\pm}1.6$으로 1군의 $0.2{\pm}0.2$에 비해 높았으나(P=0.0961), 통계적인 유의성은 없었다. 2명의 환자에서 8,272-8,281(CCCCCTCTA) 부위 염기서열 누락을 관찰되었다. 단백뇨 정도에 따라 분류한 두군 모두에서 각각 한명씩 염기 서열의 누락이 있었다. 누락된 부위는 미토콘드리아 유래 발현되는 단백질 서열 등에 관련 없는 비부호화부위(non coding region) 이었다. 8,272-8,281 부위를 제외한 미토콘드리아 DNA 염기서열은 모두 정상이었다. 결론: 소아 IgA 신병증에서도 mtDNA common deletion이 증명됨으로해서 향후 소아 IgA 신병증에서 미토콘드리아의 기능 이상이 진행성 임상적 경과에 어떠한 영향을 미칠 수 있는 지에 대한 추가 연구가 필요하다고 생각한다.

• Clinical and Experimental Pediatrics
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• 제45권3호
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• pp.302-310
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• 2002

목 적: 본 연구에서는 임상적으로 XLA로 진단받고 현재 치료 중인 국내 환아 세가족의 네명의 환아와 모친 등을 대상으로 말초혈액 단핵구의 Btk 단백질 발현과 Btk 유전자 변이를 분석하고자 하였다. 방 법: 말초혈액 단핵구의 Btk 발현도를 항 Btk 항체를 이용한 유세포측정을 통해 분석하고 직접 염기서열 분석에 의해 Btk 유전자 변이를 분석하였다. 결 과 : 환아들의 B 림프구의 발현은 2.1% 미만으로 정상인에 비해 매우 저하되어 있었으며 유세포 측정에 의한 환아 단핵구 유래 Btk 단백질 발현도 1.0% 이하로 정상인에 비해 매우 감소되었다. 유전자 변이 분석 결과 XLA 가족 1과 3에서는 각각 intron 18과 intron 1의 짜집기 공여 위치 부위에서 1개의 점 돌연변이가 발견되었으며 cDNA상 짜집기 오류 현상을 야기하였다. 그리고 XLA 가족 2의 경우 exon 10을 포함하는 980 bp의 유전자 결손(intron 9＋191T부터 intron 10-215C까지)이 발견되었으며 세계적으로 처음 보고되는 새로운 유전자 변이였다. 또한 가족 2의 경우 가족 중 환아에서 만 Btk 단백질 결핍 및 유전자 변이를 진단하여 국내 XLA의 환아 중 최초의 산발적인 발병 양상을 확인하였다. 결 론: 본 연구 결과를 종합해 볼 때 임상적으로 XLA로 진단된 환아와 가족에 대한 항 Btk 항체를 이용한 유세포측정 방법은 XLA 환아 및 보인자의 진단에 매우 유용한 방법으로 생각된다. 또한 분자유전학 기법을 이용하여 Btk의 noncoding region을 포함한 광범위한 유전자 영역의 염기서열 분석을 시행한 결과 새로운 1개의 유전자 결손 및 2개의 점돌연변이에 의한 짜집기 오류를 확인하여 XLA를 최종 확진할 수 있었다.

• Clinical and Experimental Pediatrics
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• 제51권1호
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• pp.73-77
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• 2008

목 적 : p16 유전자는 염색체 9p21에 위치하는데 종양억제 유전자 중 하나로 cyclin-dependent kinase의 억제제로 작용하며 Rb 인산화를 억제한다. 다양한 종류의 종양에서 p16 유전자의 결실 또는 과메틸화가 발견되고 있는데 이는 급성림프구성백혈병에서도 흔히 발견되는 이상 소견으로 높은 빈도로 나타나고 있지만 급성림프구성백혈병의 예후와 p16 유전자의 연관성에 대해서는 아직 논란의 여지가 있다. 본 연구에서는 면역조직화학염색으로 확인한 p16 단백질의 소실과 급성림프구성백혈병 환아들의 임상 경과와의 연관성에 대하여 조사하고자 하였다. 방 법 : 1998년 1월부터 2006년 12월까지 급성림프구성백혈병으로 진단된 74명의 진단 시 골수 슬라이드에서 p16 단백질 면역조직화학염색을 하였다. 환아들의 임상 양상, 검사실 소견, 치료 후 경과에 대해서 후향적으로 조사하였다. 결 과 : 74명 중 12명에서 p16 단백질이 면역화학염색 결과 음성이었다. 이들 중 남아가 7명 여아가 5명이었으며 진단 시 연령의 중앙값은 5.8(1.3-18.8)세였다. 백혈구 수의 중앙값은 17,225 $(500-403,300)/{\mu}L$ 이었으며 면역표현형은 early pre-B CALLA (+)형이 7명, T 세포형은 5명이었다. 진단 시 예후 중간군이었던 두 명의 환아들에서 골수 재발 하였으며 3명의 환아들이 유방암의 가족력이 있었다. 4명이 사망하여 8년 생존율은 $53.5{\pm}18.7%$였다. 결 론 : p16 단백질의 소실은 소아 급성림프구성백혈병에서 불량한 예후와 연관된 인자로 추정되며 임상에서 진단 시 p16에 대한 유전자 검사뿐만 아니라 단백질에 대해서도 검사가 필요할 것으로 생각된다. 하지만 좀더 많은 환자들에 대한 분석이 더 정확한 연관성을 밝히는데 도움이 될 것으로 사료된다.