Browsing by Subject "mutation"
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Item A Novel sRNA Member of the Carbon Storage Regulatory System of Escherichia Coli(2002-12-01) Weilbacher, Thomas; Jerry SimeckaWeilbacher, Thomas S., A Novel sRNA Member of the Carbon Storage Regulatory System of Escherichi coli. Master of Science (Microbiology & Immunology), December, 2002, 57 pp., 2 tables, 12 illustrations, bibliography, 44 titles. Small untranslated RNAs (sRNAs) perform a variety of important functions in bacterial systems. The 245 nt sRNA of Escherichia coli K-12, CsrC, was uncovered using a genetic screen for genes that regulate glycogen biosynthesis. CsrC RNA binds multiple copies of CsrA, a protein that post-transcriptionally regulates central carbon flux, biofilm formation, and motility in E. coli. CsrC antagonizes the regulatory effects of CsrA, presumably by sequestering this protein. The discovery of CsrC is intriguing, in that a similar sRNA, CsrB, performs essentially the same function. Both of these sRNAs possess similar imperfect repeat sequences (18 in CsrB, 9 in CsrC), primarily localized in the loops of predicted hairpins, which may serve as CsrA binding elements. Transcription of csrC increases as the culture approaches the stationary phase of growth and is activated by CsrA and the response regulator UvrY. Complementation and in vitro transcription-translation experiments reveal that CsrA effects on csrC are mediated indirectly, through UvrY. Because CsrB and CsrC antagonize the activity of CsrA and are dependent on CsrA for their synthesis, a csrB null mutation causes a modest compensatory increase in CsrC levels and vice versa. An updated model for the signaling circuitry of the Csr system is discussed.Item FTD-PSP is an Unusual Clinical Phenotype in A Frontotemporal Dementia Patient with A Novel Progranulin Mutation(JKL International, 2021-10-01) Deng, Bin; Zheng, Zhe; Zheng, Jialing; Yang, Wanlin; Huang, Yu; Luo, Yuqi; Jin, Dana; Shen, Lu; Jin, Kunlin; Wang, QingProgranulin (GRN) mutations are a major cause of frontotemporal dementia (FTD); the spectrum of clinical phenotypes of FTD is much more extensive than previously reported. The frequency and locations of GRN mutations in Chinese patients with FTD remain uncertain. We performed cDNA sequencing in one sporadic male patient who initially presented FTD symptoms. Brain magnetic resonance imaging (MRI) and positron emission computed tomography/computed tomography (PET/CT) were applied to further confirm the diagnosis of FTD from this patient. Cellular apoptosis and survival test were performed to identify the function of GRN. We identified one novel missense GRN mutation (c.1498G>A, p.V500I) in this patient, who initially presented typical behavioral-variant frontotemporal dementia (bvFTD) features but then presented progressive supranuclear palsy (PSP) clinical characteristics 5 years after onset. Besides, WT GRN protein showed an adequate trophic stimulus to preserve the survival of SH-SY5Y cells in the medium free of serum, while GRN mutation (c.1498G>A, p.V500I) may impair the ability of supporting cell survival. This study owns significant implications for genetic counseling and clinical heterogeneity. We illustrate the fact that FTD presenting features of bvFTD and PSP in one patient could be considered as a specific phenotype in patients with GRN mutations. GRN p.V500I led to the neuronal degeneration in vitro; this finding provides a significant evidence that this mutation may be a new causative mutation in patients with FTD.Item Identification of Novel Genes Involved in Escherichia coli Biofilm Formation(2003-05-01) DesPlas, Rebecca L.; Jerry Simecka; Ming-Chi WuDesPlas, Rebecca L., Identification of Novel Genes Involved in Escherichia coli Biofilm Formation. Master of Science (Microbiology), May 2003, 77 pp., 6 tables, 11 figures, references, 55 titles. Transposon mutagenesis using a miniTn10::camR transposon generated 800 random insertion mutants displaying altered biofilm phenotypes as compared to the parent strain, TRMG F/M. Transduction of the resistance marker confirmed approximately 150 biofilm mutants. Amplifications of the insertion sites, nucleotide sequencing and BLAST searches against E. coli K-12 genomic databases, identified118 of these sites. Many of the interrupted genes are not known to be associated with biofilm formation. Four mutations were transduced into E. coli K-12 MG1655, creating altered biofilm phenotypes. A plasmid clone of the nhaAR operon complemented the corresponding mutations. Results indicate that the genes identified in this study influence biofilm formation. However, further studies are needed to determine the degree of impact in a wild type strain background.