• Title/Summary/Keyword: RAD51

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Gene Expression Biodosimetry: Quantitative Assessment of Radiation Dose with Total Body Exposure of Rats

  • Saberi, Alihossein;Khodamoradi, Ehsan;Birgani, Mohammad Javad Tahmasebi;Makvandi, Manoochehr
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.18
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    • pp.8553-8557
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    • 2016
  • Background: Accurate dose assessment and correct identification of irradiated from non-irradiated people are goals of biological dosimetry in radiation accidents. Objectives: Changes in the FDXR and the RAD51 gene expression (GE) levels were here analyzed in response to total body exposure (TBE) to a 6 MV x-ray beam in rats. We determined the accuracy for absolute quantification of GE to predict the dose at 24 hours. Materials and Methods: For this in vivo experimental study, using simple randomized sampling, peripheral blood samples were collected from a total of 20 Wistar rats at 24 hours following exposure of total body to 6 MV X-ray beam energy with doses (0.2, 0.5, 2 and 4 Gy) for TBE in Linac Varian 2100C/D (Varian, USA) in Golestan Hospital, in Ahvaz, Iran. Also, 9 rats was irradiated with a 6MV X-ray beam at doses of 1, 2, 3 Gy in 6MV energy as a validation group. A sham group was also included. After RNA extraction and DNA synthesis, GE changes were measured by the QRT-PCR technique and an absolute quantification strategy by taqman methodology in peripheral blood from rats. ROC analysis was used to distinguish irradiated from non-irradiated samples (qualitative dose assessment) at a dose of 2 Gy. Results: The best fits for mean of responses were polynomial equations with a R2 of 0.98 and 0.90 (for FDXR and RAD51 dose response curves, respectively). Dose response of the FDXR gene produced a better mean dose estimation of irradiated "validation" samples compared to the RAD51 gene at doses of 1, 2 and 3 Gy. FDXR gene expression separated the irradiated rats from controls with a sensitivity, specificity and accuracy of 87.5%, 83.5% and 81.3%, respectively, 24 hours after dose of 2 Gy. These values were significantly (p<0.05) higher than the 75%, 75% and 75%, respectively, obtained using gene expression of RAD51 analysis at a dose of 2 Gy. Conclusions: Collectively, these data suggest that absolute quantification by gel purified quantitative RT-PCR can be used to measure the mRNA copies for GE biodosimetry studies at comparable accuracy to similar methods. In the case of TBE with 6MV energy, FDXR gene expression analysis is more precise than that with RAD51 for quantitative and qualitative dose assessment.

Identification and Cloning of jipA Encoding a Polypeptide That Interacts with a Homolog of Yeast Rad6, UVSJ in Aspergillus nidulans

  • Cho, Jae-Han;Yun, Seok-Soong;Jang, Young-Kug;Cha, Mee-Jeong;Kwon, Nak-Jung;Chae, Suhn-Kee
    • Journal of Microbiology
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    • v.41 no.1
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    • pp.46-51
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    • 2003
  • RAD6 in yeast mediates postreplication DNA repair and is responsible for DNA-damage induced mutations. RAD6 encodes ubiquitin-conjugating enzyme that is well conserved among eukaryotic organisms. However, the molecular targets and consequences of their ubiquitination by Rad6 have remained elusive. In Aspergillus nidulans, a RAD6 homolog has been isolated and shown to be an allele of uvs). We screened a CDNA library to isolate UVSJ-interacting proteins by the yeast two-hybrid system. JIPA was identified as an interactor of UVSJ. Their interaction was confirmed in vitro by a GST-pull down assay. JIPA was also able to interact with mutant UVSJ proteins, UVSJl and the active site cysteine mutant UVSJ-C88A. The N- and the C-terminal regions of UVSJ required for the interaction with UVSH, a RAD18 homolog of yeast which physically interacts with Rad6, were not necessary for the JIPA and UVSJ interactions. About 1.4 kb jipA transcript was detected in Northern analysis and its amount was not significantly increased in response to DNA-damaging agents. A genomic DNA clone of the jipA gene was isolated from a chromosome I specific genomic library by PCR-sib selection. Sequence determination of genomic and cDNA of jipA revealed an ORF of 893 bp interrupted by 2 introns, encoding a putative polypeptide of 262 amino acids. JIPA has 33% amino acid sequence identity to TIP41 of Saccharomyces cerevisiae which negatively regulates the TOR signaling pathway.

A COMPARISON STUDY ON THE COMMUNICATIVE INTENT OF CHILDREN WITH REACTIVE ATTACHMENT DISORDER AND DEVELOPMENTAL LANGUAGE DISORDER (반응성 애착장애아와 발달성 언어장애아의 의사소통 의도 비교 연구)

  • Lee, Kyung-Sook;Lee, Ho-Boon;Shin, Cheong-Hyoun;Noh, Kyung-Sun;Im, Yun-Hwa
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.8 no.2
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    • pp.207-216
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    • 1997
  • This study was conducted to investigate the communicative intent between Reactive Attachment Disorder(RAD) and Developmental Language Disorder(DLD). The subject of this study were 20 27-51 monthold children(10 RAD Children, 10 DLD children) functioning at similar stage of language development. The communicative intent was investigated vertical and horizontal dimension. Rating of vertical communicative intent was based on the assessment scales devised by Wetherby and Prutting(1984). Horizontal dimension was measured by the assessment guidelines of Wetherby and Prizant(1989). All the data were rated by two rators independantly. 1) In communicative intent, vertical development level of DLD children was more sophiscated than that of RAD children. 2) DLD children expressed more horizontal communicative intent than RAD children. The percentage of the three major categories(behavioral regulation, social interaction, and joint attention) of communicative intent in DLD children was lined up social interaction>joint attention>behavioral regulation. On the contrary, RAD children displayed in order of behavioral regulation>social interaction>joint attention. In addition, DLD children showed diversely as compared with RAD children.

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2 CASES OF CAROTID ARTERY RUPTURE FOLLOWING TOTAL LARYNGECTOMY (후두전적출술 후에 발생한 경동맥 파열 2례)

  • 이흥만;이광선;황순재;추광철
    • Proceedings of the KOR-BRONCHOESO Conference
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    • 1987.05a
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    • pp.22.2-22
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    • 1987
  • 경동맥 파열은 악성 종양으로 인한 두경부 수술의 1-5%에서 발생하고 80%의 사망률과 생존자의 50%에서 신경학적 후유증을 나타낸다. 저자들은 수술전ㆍ후 방사선치료를 받은 환자 2례에서 경동맥파열을 경험하였다. 제 1례는 51세의 남자로서 후두암($T_4$NoMx)으로 후두전적출술과 6120 rad의 수술후 방사선 치료 후 좌측 악하 부위에 악성 종양의 경동맥 침윤으로 시험적 수술후 6일만에 경동맥 파열로 사망하였다. 제 2례는 51세의 남자로서 하인두암($T_3$$N_2$Mx)으로 7200 rad의 수술전 방사선치료후 악성 종양의 재발로 후두전적출술과 일측의 근치적 경부곽청술후 누공을 형성하여 수술후 14일만에 경동맥 파열로 사망하였다.

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Hop2 and Sae3 Are Required for Dmc1-Mediated Double-Strand Break Repair via Homolog Bias during Meiosis

  • Cho, Hong-Rae;Kong, Yoon-Ju;Hong, Soo-Gil;Kim, Keun Pil
    • Molecules and Cells
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    • v.39 no.7
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    • pp.550-556
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    • 2016
  • During meiosis, exchange of DNA segments occurs between paired homologous chromosomes in order to produce recombinant chromosomes, helping to increase genetic diversity within a species. This genetic exchange process is tightly controlled by the eukaryotic RecA homologs Rad51 and Dmc1, which are involved in strand exchange of meiotic recombination, with Rad51 participating specifically in mitotic recombination. Meiotic recombination requires an interaction between homologous chromosomes to repair programmed double-strand breaks (DSBs). In this study, we investigated the budding yeast meiosis-specific proteins Hop2 and Sae3, which function in the Dmc1-dependent pathway. This pathway mediates the homology searching and strand invasion processes. Mek1 kinase participates in switching meiotic recombination from sister bias to homolog bias after DSB formation. In the absence of Hop2 and Sae3, DSBs were produced normally, but showed defects in the DSB-to-single-end invasion transition mediated by Dmc1 and auxiliary factors, and mutant strains failed to complete proper chromosome segregation. However, in the absence of Mek1 kinase activity, Rad51-dependent recombination progressed via sister bias in the $hop2{\Delta}$ or $sae3{\Delta}$ mutants, even in the presence of Dmc1. Thus, Hop2 and Sae3 actively modulate Dmc1-dependent recombination, effectively progressing homolog bias, a process requiring Mek1 kinase activation.

Identification of a Regulatory Element Required for 3’-End Formation in Transcripts of rhp51$^+$, a recA Homolog of the Fission Yeast Schizosaccharomyces pombe

  • Yeun Kyu Jang
    • Animal cells and systems
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    • v.3 no.4
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    • pp.413-415
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    • 1999
  • Our previous report demonstrated that the rhp51$^+$, a recA and RAD51 homolog of the fission yeast, encodes three transcripts of 1.9, 1.6 and 1.3 kb which have at least six polyadenylation sites. The 3'-end of the gene alone can direct the formation of multiple, discrete 3'ends of the transcripts. To identify the regulatory element required for the 3'-end formation of -rhp51$^+$ deletion mapping analysis was performed. Northern blot analysis revealed that the 254-bp DNA fragment including 4 distinct poly (A) sites downstream from the Hindlll site, is crucial for normal 3'-end formation. Deletion of the 3'-terminal AU rich region caused appearance of read-through RNA, leading to enhancement of survival rate of the rhp51 deletion mutant in response to DNA damaging agent, methylmethane sulfonate (MMS). The results imply that the rhp51$^+$ system may be useful for molecular analysis of the 3'-end formation of RNA in the fission yeast.

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