• International Journal of Advanced Culture Technology
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• v.9 no.3
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• pp.112-116
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• 2021

The aim of this study is to analyze the complementizer that-deletion in embedded complement clauses in English. This paper is concerned with the alternation between the overt that-complementizer and the zero complementizer by the complementizer deletion (C-deletion or that-deletion) in constructions with a nominal complement that-clause, i.e. [VP Verb [CP that-TP]]. In this paper, we compare that-complementation and zero-complementation in a diachronic grammaticalization and corpus, and show that the complementizer that has its origin in pronouns diachronically and finally becomes to form a C-head of the functional category CP. We provide the syntactic and semantic explanation on the optionality of that-deletion while answering the question why and how that-deletion is getting increasing in use especially with the verb, think, in the informal contexts. With the major causes for the currently increasing use of that-deletion, we are concerned with the contexts in which the overt complementizers or the covert complementizers are preferred.

• The Journal of Korean Society of Virology
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• v.30 no.3
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• pp.161-170
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• 2000

Continuous efforts are being made to find effective therapeutic agents against HIV-1, the causative agents of AIDS. In this study, we developed a cell-based assay system employing a trans-complementation for production of recombinant viruses which are capable of undergoing one round of replication in CD4+ T cells. This assay system was tested for ability to screen the agents that act at late stage of HIV-1 life cycle. The effect of a protease inhibitor on the trans-complementation assay was assessed. Recombinant HIV-1 viruses were prepared from a trans-complementation in the presence of various concentrations of protease inhibitor. Inhibition of single round infection of these recombinant viruses by protease inhibitor was observed to be a dose-dependent manner. Inhibitory effects of a protease inhibitor on HIV-1 Gag polyprotein processing by HIV-1 protease was detected at concentrations of the protease inhibitor compatible with inhibition of virus infection, confirming that the corresponding step was involved in the inhibitory mechanism of this compound. Together, these results provide evidence that a cell-based assay system established in this study can be used to screen the agents that target the late stage of HIV-1 life cycle.

• International Journal of Stem Cells
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• v.15 no.2
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• pp.113-121
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• 2022

The ultimate goal of regenerative medicine is to replace damaged cells, tissues or whole organs, in order to restore their proper function. Stem cell related technologies promise to generate transplants from the patients' own cells. Novel approaches such as blastocyst complementation combined with genome editing techniques open up new perspectives for organ replacement therapies. This review summarizes recent advances in the field and highlights the challenges that still remain to be addressed.

• BMB Reports
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• v.46 no.1
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• pp.53-58
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• 2013

We constructed deletion mutants and seven point mutants by polymerase chain reaction to investigate the specificity of feline foamy virus integrase functional domains. Complementation reactions were performed for three enzymatic activities such as 3'-end processing, strand transfer, and disintegration. The complementation reactions with deletion mutants showed several activities for 3'-end processing and strand transfer. The conserved central domain and the combination of the N-terminal or C-terminal domains increased disintegration activity significantly. In the complementation reactions between deletion and point mutants, the combination between D107V and deletion mutants revealed 3'-end processing activities, but the combination with others did not have any activity, including strand transfer activities. Disintegration activity increased evenly, except the combination with glutamic acid 200. These results suggest that an intact central domain mediates enzymatic activities but fails to show these activities in the absence of the N-terminal or C-terminal domains.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.1
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• pp.2-9
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• 2023

Mammalian eyes have a limited ability to regenerate once neurons degenerate. This results in visual impairment that impacts the quality of life among adult populations as well as in young children leading to lifelong consequences. Various therapies are in development to restore vision, and these include gene therapy, stem cell therapy, in-vivo transdifferentiation, and transplantation of a patient's whole eye obtained from interspecies blastocyst complementation. This review discusses advances in the research as well as hurdles that need to be resolved to have a successful restoration of vision.

• Molecules and Cells
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• v.27 no.1
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• pp.83-88
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• 2009

Amino acid homology analysis predicted that rbmD, a putative glycosyltransferase from Streptomyces ribosidificus ATCC 21294, has the highest homology with neoD in neomycin biosynthesis. S. fradiae BS1, in which the production of neomycin was abolished, was generated by disruption of the neoD gene in the neomycin producer S. fradiae. The restoration of neomycin by self complementation suggested that there was no polar effect in the mutant. In addition, S. fradiae BS6 was created with complementation by rbmD in S. fradiae BS1, and secondary metabolite analysis by ESI/MS, LC/MS and MS/MS showed the restoration of neomycin production in S. fradiae BS6. These gene inactivation and complementation studies suggested that, like neoD, rbmD functions as a 2-N-acetlyglucosaminyltransferase and demonstrated the potential for the generation of novel aminoglycoside antibiotics using glycosyltransferases in vivo.

• Journal of Microbiology and Biotechnology
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• v.26 no.1
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• pp.66-71
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• 2016

PikD is a widely known pathway-specific regulator for controlling pikromycin production in Streptomyces venezuelae ATCC 15439, which is a representative of the large ATP-binding regulator of the LuxR family (LAL) in Streptomyces sp. RapH and FkbN also belong to the LAL family of transcriptional regulators, which show greatest homology with the ATP-binding motif and helix-turn-helix DNA-binding motif of PikD. Overexpression of pikD and heterologous expression of rapH and fkbN led to enhanced production of pikromycin by approximately 1.8-, 1.6-, and 1.6-fold in S. venezuelae, respectively. Cross-complementation of rapH and fkbN in the pikD deletion mutant (ΔpikD) restored pikromycin and derived macrolactone production. Overall, these results show that heterologous expression of rapH and fkbN leads to the overproduction of pikromycin and its congeners from the pikromycin biosynthetic pathway in S. venezuelae, and they have the same functionality as the pathwayspecific transcriptional activator for the pikromycin biosynthetic pathway in the ΔpikD strain. These results also show extensive "cross-communication" between pathway-specific regulators of streptomycetes and suggest revision of the current paradigm for pathwayspecific versus global regulation of secondary metabolism in Streptomyces species.

• Korean Journal of Microbiology
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• v.27 no.2
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• pp.77-84
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• 1989

The temperature sensitive (ts) mutation on RNA1 gene of Saccharomyces cerevisiae prevents growth at restrictive temperature ($36^{\circ}C$) by accumulation of precursor tRNA, rRNA and mRNA (Hutchison et al., 1969; Shiokawa and Pogo, 1974; Hopper et al., 1978). RNA1 gene was cloned by complementation of the temperature sensitive growth defect of an rna1-1 mutant strain and identified by retransformation and concomitant loss of recombinant plasmid on non-selective condition. By deletion mapping, it was found that RNA1 gene resides within 3.5kb of BgII fragment.

• Journal of Microbiology and Biotechnology
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• v.5 no.5
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• pp.250-256
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• 1995

The ddh gene encoding meso-diaminopimelate (meso-DAP)-dehydrogenase (DDH) in Brevibacterium lactofermentum was isolated by complementation of the Escherichia coli dapD mutation. It was supposed from subcloning experiments and complementation tests that the evidence for DDH activity appeared in about 2.5 kb Xhol fragmented genome. The 2.5 kb Xhol fragment containing the ddh gene was sequenced, and an open reading frame of 960 bp encoding a polypeptide comprising 320 amino acids was found. Computer analysis indicated that the deduced amino acid of the B. lactofermentum ddh gene showed a high homology with that of the Corynebacterium glutamicum ddh gene.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.802-805
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• 2001

The dapD gene of Brevibacterium lactofermentum encoding tetrahydrodipicolinate N-succinyl transferase, one of the enzymes involved in lysine biosynthesis, was cloned by complementation of Escherichia coli dapD mutnat. The recombinant plasmid pLS1 was found to contain a 3.6 kb DNA fragment. Southern hybridization analysis confirmed that the cloned DNA fragment originated from B. lactofermentum. The data of L-lysine production showed that the B. lactofermentum dapD gene was expressed in E. coli.