• Journal of Microbiology and Biotechnology
• /
• 제16권9호
• /
• pp.1453-1458
• /
• 2006

PKR-like endoplasmic reticulum (ER) kinase (PERK) is a type I transmembrane ER-resident protein containing a cytoplasmic catalytic domain with a Ser/Thr kinase activity, which is most closely related to the eukaryotic translation initiation factor-$2{\alpha}$ ($eIF2{\alpha}$) kinase PKR involved in the antiviral defense pathway by interferon. We cloned and expressed the PERK C-terminal kinase domain (cPERK) in Escherichia coli. Like PERK activation in cells under ER stress, wild-type cPERK underwent autophosphorylation when overexpressed in E. coli, whereas the cPERK(K621M) with a methionine substitution for the lysine at amino acid 621 lost the autophosphorylation activity. The activated form cPERK which was purified to near homogeneity, formed an oligomer and was able to trans-phosphorylate specifically its cellular substrate $eIF2{\alpha}$. Two-dimensional phosphoamino acids analysis revealed that phosphorylation of cPERK occurs at the Ser and Thr residues. The functionally active recombinant cPERK, and its inactive mutant should be useful for the analysis of biochemical functions of PERK and for the determination of their three-dimensional structures.

• BMB Reports
• /
• 제37권4호
• /
• pp.474-479
• /
• 2004

The expressed sequence tag (EST) effort in Toxoplasma gondii has generated a substantial amount of gene information. To exploit this valuable resource, we chose to study tgd057, a novel gene identified by a large number of ESTs that otherwise show no significant match to known sequences in the database. Northern analysis showed that tgd057 is transcribed in this tachyzoite. The complete cDNA sequence of tgd057 is 1169 bp in length. Sequence analysis revealed that tgd057 possibly adopts two polyadenylation sites, utilizes the fourth in-frame ATG for translation initiation, and codes for a secretory protein. The longest open reading frame for the tgd057 gene was cloned and expressed as a recombinant protein (rd57) in Escherichia coli. Western analysis revealed that serum against rd57 recognized a molecule of ~21 kDa in the tachyzoite protein extract. This suggests that the tgd057 gene is expressed in vivo in the parasite.

• Molecules and Cells
• /
• 제40권1호
• /
• pp.66-72
• /
• 2017

Pathological hypertrophy of the heart is closely associated with endoplasmic reticulum stress (ERS), leading to maladaptations such as myocardial fibrosis, induction of apoptosis, and cardiac dysfunctions. Salubrinal is a known selective inhibitor of protein phosphatase 1 (PP1) complex involving dephosphorylation of phospho-eukaryotic translation initiation factor 2 subunit $(p-eIF2)-{\alpha}$, the key signaling process in the ERS pathway. In this study, the effects of salubrinal were examined on cardiac hypertrophy using the mouse model of transverse aortic constriction (TAC) and cell model of neonatal rat ventricular myocytes (NRVMs). Treatment of TAC-induced mice with salubrinal ($0.5mg{\cdot}kg^{-1}{\cdot}day^{-1}$) alleviated cardiac hypertrophy and tissue fibrosis. Salubrinal also alleviated hypertrophic growth in endothelin 1 (ET1)-treated NRVMs. Therefore, the present results suggest that salubrinal may be a potentially efficacious drug for treating pathological cardiac remodeling.

• The Plant Pathology Journal
• /
• 제17권1호
• /
• pp.22-28
• /
• 2001

Barley yellow dwarf virus PAV (BYDV-PAV) has a 5.7-kb positive-sense single-stranded RNA genome that contains six open reading frames (ORFs). BYDV-PAV produces three subgenomic RNAs (sgRNAs). The largest of which encodes the coat, 17-kDa, and readthrough proteins from two initiation codons. To investigate the role of intergenic and 3'-proximal noncoding regions (NCRs) in coat protein (CP) expression and BYDV-PAV replication, a full-length infectious cDNA of the RNA genome of an Illinois isolate of BYDV-PAV was constructed downstream of the Cauliflower mosaic virus-35S promoter. Linear DNA molecules of these cDNAs were infectious, expressed the 22-kDa CP, and produced both genomic RNA sgRNAs in ratios similar to those observed in protoplasts inoculated with viral RNA. The portion of 5'NCR of sgRNA1 between ORFs 2 and 3 was not required for, but enhanced translation of CP from ORF3. Mutants containing deletions in the NCR downstream of ORF5 failed to replicate in oat protoplasts. These results indicate that an intact 3$^1$NCR is required for BYDV-PAV replication.

• 생명과학회지
• /
• 제7권3호
• /
• pp.167-171
• /
• 1997

번역개시 및 인산화의 조절에 관여하는 RNA와 단백질의 결합 및 인식기작을 연구하기 위해서[$\alpha$^{-32}$P] UMP-labeled HIV Rev-responsive element(RRE) RNA를 이용한 affinity screening에 이해서 Hela ZA-PII cDNA library로부터 이중선RNA결합단백질의 cDNA (RBFII)를 분리하였다. RBFII의 cDNA에 대한 염기서열을 결정하였으며 기존에 연구된 바 있는 RBFII(RBF 또는 TRBP로 보고되었으며 본 연구에서는 RBFII와 구분하기 위해 RBFI으로 명명)과 대부분의 경우 공통적인 ORF를 지니는 것으로 나타났다. 그러나 5’말단에서는 공통적인 ORF 가 RBFI의 경우 21개의 아미노산을 의미하는 63 nt가 Lac-Z의 N-말단에 연결된데 비해서 특이한 46개 아미노기를 의미하는 138nt가 존재함이 밝혀졌다. 5’-말단에 처음 나타나는 ATG 및 부근의 염기서열을 분석해 볼 때 양 cDNA는 5’말단이 완전하지 않은 것으로 사료된다.

• 대한의생명과학회지
• /
• 제24권4호
• /
• pp.426-429
• /
• 2018

Chronic eosinophilic leukemia (CEL) is characterized by eosinophilia and organ damage. Imatinib is widely used for treating CEL, chronic myeloid leukemia (CML) and acute myeloid leukemia (AML). Unfortunately, the cancer cells gain resistance against the drug after prolonged molecular-targeted therapies. Imatinib-resistant EoL-1 (EoL-1-IR) cells were produced from chronic eosinophilic leukemia cells (EoL-1) after treatment with imatinib for a long duration. Two-dimensional electrophoresis (2-DE) analysis revealed numerous protein variations in the EoL-1 and EoL-1-IR sub-types. Compared to the EoL-1 cells, expression levels of TIP49, RBBP7, ${\alpha}$-enolase, adenosine deaminase, C protein, galactokinase, eukaryotic translation initiation factor, $IFN-{\gamma}$, and human protein homologous to DROER were increased, whereas core I protein, proteasome subunit p42, heterogeneous ribonuclear particle protein, chain B, and nucleoside diphosphate were decreased in the EoL-1-IR cells. Taken together, these results contribute to understanding the pathogenic mechanism of drug-resistant diseases.

• The Plant Pathology Journal
• /
• 제39권1호
• /
• pp.28-38
• /
• 2023

Plant viruses are responsible for worldwide production losses of numerous economically important crops. The most common plant RNA viruses are positivesense single-stranded RNA viruses [(+)ss RNA viruses]. These viruses have small genomes that encode a limited number of proteins. The viruses depend on their host's machinery for the replication of their RNA genome, assembly, movement, and attraction to the vectors for dispersal. Recently researchers have reported that chloroplast proteins are crucial for replicating (+)ss plant RNA viruses. Some chloroplast proteins, including translation initiation factor [eIF(iso)4E] and 75 DEAD-box RNA helicase RH8, help viruses fulfill their infection cycle in plants. In contrast, other chloroplast proteins such as PAP2.1, PSaC, and ATPsyn-α play active roles in plant defense against viruses. This is also consistent with the idea that reactive oxygen species, salicylic acid, jasmonic acid, and abscisic acid are produced in chloroplast. However, knowledge of molecular mechanisms and functions underlying these chloroplast host factors during the virus infection is still scarce and remains largely unknown. Our review briefly summarizes the latest knowledge regarding the possible role of chloroplast in plant virus replication, emphasizing chloroplast-related proteins. We have highlighted current advances regarding chloroplast-related proteins' role in replicating plant (+)ss RNA viruses.

• Asian-Australasian Journal of Animal Sciences
• /
• 제33권6호
• /
• pp.1012-1022
• /
• 2020

Objective: Caseins and fatty acids of milk are synthesized and secreted by the epithelial cells of the mammary gland. All-trans retinoic acid (ATRA), an active metabolite of vitamin A, has been shown to promote mammary development. This study was conducted to determine the effect of ATRA on casein synthesis and fatty acid composition in MAC-T cells. Methods: MAC-T cells were allowed to differentiate for 4 d, treated with ATRA (0, 1.0, 1.5, and 2.0 μM), and incubated for 3 d. We analyzed the fatty acid composition, the mRNA expression of casein and fatty acid synthesis-related genes, and the phosphorylation of casein synthesis-related proteins of MAC-T cells by gas chromatography, quantitative polymerase chain reaction, and western blotting, respectively. Results: In MAC-T cells, ATRA increased the mRNA levels of α_S1-casein and β-casein, janus kinase 2 (JAK2) and E74-like factor 5 of the signal transducer and activator of transcription 5 β (STAT5-β) pathway, ribosomal protein S6 kinase beta-1 (S6K1) and eukaryotic translation initiation factor 4E binding protein 1 of the mammalian target of rapamycin (mTOR) pathway, inhibited the mRNA expression of phosphoinositide 3-kinase and eukaryotic initiation factor 4E of the mTOR pathway, and promoted the phosphorylation of STAT5-β and S6K1 proteins. Additionally, ATRA increased the de novo synthesis of fatty acids, reduced the content of long-chain fatty acids, the ratio of monounsaturated fatty acids to saturated fatty acids (SFA), the ratio of polyunsaturated fatty acids (PUFA) to SFA, and the ratio of ω-6 to ω-3 PUFA. The mRNA levels of acetyl-CoA carboxylase 1, fatty acid synthase, lipoprotein lipase, stearoyl-CoA desaturase, peroxisome proliferator-activated receptor gamma, and sterol regulatory element-binding protein 1 (SREBP1) were enhanced by ATRA. Conclusion: ATRA promotes the synthesis of casein by regulating JAK2/STAT5 pathway and downstream mTOR signaling pathway, and it improves the fatty acid composition of MAC-T cells by regulating SREBP1-related genes.

• 한국미생물·생명공학회지
• /
• 제31권2호
• /
• pp.111-116
• /
• 2003

Xylan 분해 균주인 Bacillus stearothermophilus No. 236 분리균의 $\beta$-xylosidase 생산 유전자(xylA)의 염기 서열 및 transcription start site를 결정한 이전 연구 결과에 의하면 xylA 유전자는 매우 특이하게 UUG codon에서 translation이 시작되며 initiation codon 15dp 윗쪽에는 promoter로 추정되는 염기 서열을 가지고 있는 것으로 분석되었다. 이와 같은 xylA 유전자 promoter region의 구조는 E. coli에 클로닝된 xalA 유전자를 이용한 실험 결과로도 확인되었다. xalA promoter의 -10 element는 CATAAT로서 6개의 염기 중 5개가 그리고 -35 element의 경우는 TTGTTA로서 6개의 염기 중 4개가 consensus sequence와 일치되었으나 두 hexamer 사이의 거리가 최적 거리에서 크게 벗어난 12 bp인 것으로 분석되었다. 본 연구에서는 $\beta$-xylosidase의 대량 생산을 위한 연구의 일환으로 xalA promoter sequence의 체계적 구조 변화에 의한 promoter strength에 미치는 효과를 E. coli와 B. subtilis두 숙주 세포에서 조사 분석해 본 결과, 첫째로 두 promoter elements사이의 거리를 최적거리인 17 bp로 바꾸었을 때 xalA의 발현율은 E. coli에서는 1.6배, B. subtilis에서는 2.5배 정도 증가함을 보여주었다. 그리고 -35 element는 consensus sequence와 같이 5'쪽에서 네번째 위치에 있는 T$\longrightarrow$A로 변이 시켰을 때 E. coli경우 2.3배, 특히 B. subtilis에서는 35배나 되는 가장 높은 promoter 활성의 증가를 보였다. 그러나 -10 sequence의 경우 consensus sequence와 같이 5' 쪽에서 첫번째 위치에 있는 C$\longrightarrow$T로 transition시켰을 때 예상외로 오히려 발현율이 5~15배까지 낮아지는 특이한 결과를 얻었다. 따라서 본 연구 결과 xalA promoter의 경우 -10 sequence인 CATAAT의 C와 -35 element의 두 염기가 promoter활성에 있어 가장 중요한 염기임을 알 수 있었다.

• 생명과학회지
• /
• 제23권7호
• /
• pp.941-946
• /
• 2013

신경세포의 가지돌기 내 단백질합성은 필요한 단백질을 실시간으로 제공할 수 있는 이점을 제공한다. 본 연구에서는 단백질합성인자 eIF4E와 그 억제 단백질인 eIF4EBP1의 발생단계별 표현을 배양한 해마신경세포를 면역 염색하여 조사하였다. eIF4E는 가지돌기에 점박이 모양으로 표현되었으며, 핵에는 표현되지 않았다. 그러나 eIF4EBP1는 가지돌기 뿐 아니라 발생초기(DIV 0.5)부터 핵에서 표현되었으며 성숙한 세포에서 핵에 더욱 뚜렷이 표현되었다. eIF4E 혹은 eIF4EBP1의 PSD95과의 colocalization은 $39.1{\pm}9.6%$ 및 $70.5{\pm}5.2%$ (DIV 7), $57.7{\pm}8.2%$ 및 $36.0{\pm}3.1%$ (DIV 10), $29.9{\pm}2.9%$ 및 $40.2{\pm}11.7%$ (DIV 20)이었다. eIF4E와 eIF4EBP1의 colocalizatin은 $18.5{\pm}2.6%$ (DIV 7), $11.1{\pm}3.9%$ (DIV 10), $38.6{\pm}5.6%$ (DIV 20)이었다. 이 결과는 eIF4E 및 eIF4EBP1의 많은 부분이 연접후에 위치하며, 발생초기에는 eIF4E가 활동적인 형태로 존재하지만, 성숙 신경세포에서는 eIF4EBP1과 결합하여 비활성적인 형태로 존재함을 의미한다.