DNA polymerases have been isolated from muscle and melanoma tissues of Xiphophorus, which are similar to retroviral RNA-dependent DNA polymerases as they prefer RNA to DNA templates. They appear to associate with submicroscopic structures which exhibit a density of about 1.13 g/ml after sucrose-density-gradient centrifugation. The RNA-dependent-DNA-polymerase-like enzymes could be separated from the DNA-dependent DNA polymerases by DEAE-cellulose chromatography. Further purification on phosphocellulose revealed that the muscle enzyme eluted at the void volume and at about 0.6 M KCl, whereas most of the melanoma enzyme eluted at 0.1 M KCl. Comparison of the template primer specificities of the muscle and melanoma enzymes with those of known DNA polymerases showed obvious similarities to the RNA-dependent DNA polymerase isolated from Rous sarcoma virus.
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http://dx.doi.org/10.1111/j.1432-1033.1990.tb15403.x | DOI Listing |
Hum Cell
January 2025
Department of Tumor Pathology, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuoka-Shimoaizuki, Eiheiji, Fukui, 910-1193, Japan.
Only a few human ovarian endometrioid carcinoma cell lines are currently available, partly due to the difficulty of establishing cell lines from low-grade cancers. Here, using a cell immortalization strategy consisting of i) inactivation of the p16-pRb pathway by constitutive expression of mutant cyclin-dependent kinase 4 (R24C) (CDK4) and cyclin D1, and ii) acquisition of telomerase reverse transcriptase (TERT) activity, we established a human ovarian endometrioid carcinoma cell line from a 46-year-old Japanese woman. That line, designated JFE-21, has proliferated continuously for over 6 months with a doubling time of ~ 55 h.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
Achieving targeted hypermutation of specific genomic sequences without affecting other regions remains a key challenge in continuous evolution. To address this, we evolved a T7 RNA polymerase (RNAP) mutant that synthesizes single-stranded DNA (ssDNA) instead of RNA in vivo, while still exclusively recognizing the T7 promoter. By increasing the error rate of the T7 RNAP mutant, it generates mutated ssDNA that recombines with homologous sequences in the genome, leading to targeted genomic hypermutation.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, United States.
Growth in the development of engineered polymerases for synthetic biology has led to renewed interest in assays that can measure the fidelity of polymerases that are capable of synthesizing artificial genetic polymers (XNAs). Conventional approaches require purifying the XNA intermediate of a replication cycle (DNA → XNA → DNA) by denaturing polyacrylamide gel electrophoresis, which is a slow, costly, and inefficient process that requires a large-scale transcription reaction and careful extraction of the XNA strand from the gel slice. In an effort to streamline the assay, we developed a purification-free approach in which the XNA transcription and reverse transcription steps occur inside the matrix of a hydrogel-coated magnetic particle.
View Article and Find Full Text PDFChem Asian J
January 2025
Indian Institute of Science Education and Research Bhopa;, Chemistry, IISER Bhopal, Chemistry, #229,, Academic Building #2, Bhopal bypass road, Bhauri, 462066, Bhopal, INDIA.
Polymerases erroneously incorporate Guanine-Thymine (dG•dT) mismatches in genomic DNA that further evades repair by transient sampling of tautomeric/ionic states compromising fidelity of repairing dG•dT mismatches. In conjunction, significant frequency of ribose (mis)incorporation in duplex DNA permits for misincorporated-mismatch in the genome. Ribose incorporated G(rG) mismatched with T(rG•dT) is the most stable across all misincorporated-mismatch calling into question the conformational consequences of the ribose sugar in addition to the mismatch.
View Article and Find Full Text PDFMol Biol Rep
January 2025
School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 102488, People's Republic of China.
Background: Paeonia lactiflora Pall., a member of Paeoniaceae family, is a medicinal herb widely used in traditional Chinese medicine. Chloroplasts are multifunctional organelles containing distinct genetic material.
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