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Cunningham CJ, Choi RB, Bullock WA, Robling AG. Perspective: The current state of Cre driver mouse lines in skeletal research: Challenges and opportunities. Bone 2023; 170:116719. [PMID: 36868507 PMCID: PMC10087282 DOI: 10.1016/j.bone.2023.116719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/15/2023] [Accepted: 02/19/2023] [Indexed: 03/04/2023]
Abstract
The Cre/Lox system has revolutionized the ability of biomedical researchers to ask very specific questions about the function of individual genes in specific cell types at specific times during development and/or disease progression in a variety of animal models. This is true in the skeletal biology field, and numerous Cre driver lines have been created to foster conditional gene manipulation in specific subpopulations of bone cells. However, as our ability to scrutinize these models increases, an increasing number of issues have been identified with most driver lines. All existing skeletal Cre mouse models exhibit problems in one or more of the following three areas: (1) cell type specificity-avoiding Cre expression in unintended cell types; (2) Cre inducibility-improving the dynamic range for Cre in inducible models (negligible Cre activity before induction and high Cre activity after induction); and (3) Cre toxicity-reducing the unwanted biological effects of Cre (beyond loxP recombination) on cellular processes and tissue health. These issues are hampering progress in understanding the biology of skeletal disease and aging, and consequently, identification of reliable therapeutic opportunities. Skeletal Cre models have not advanced technologically in decades despite the availability of improved tools, including multi-promoter-driven expression of permissive or fragmented recombinases, new dimerization systems, and alternative forms of recombinases and DNA sequence targets. We review the current state of skeletal Cre driver lines, and highlight some of the successes, failures, and opportunities to improve fidelity in the skeleton, based on successes pioneered in other areas of biomedical science.
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Affiliation(s)
- Connor J Cunningham
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Roy B Choi
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Alexander G Robling
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA; Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA; Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, Indianapolis, IN, USA; Indiana Center for Musculoskeletal Health, Indianapolis, IN, USA.
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Li R, Han Z, Yin Q, Li M, Zhang M, Li Z, Wang P, Jiang L, Ow DW. Target Lines for in Planta Gene Stacking in Japonica Rice. Int J Mol Sci 2022; 23:ijms23169385. [PMID: 36012650 PMCID: PMC9409015 DOI: 10.3390/ijms23169385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/11/2022] [Accepted: 08/11/2022] [Indexed: 12/02/2022] Open
Abstract
The clustering of transgenes at a chromosome location minimizes the number of segregating loci that needs to be introgressed to field cultivars. Transgenes could be efficiently stacked through site-specific recombination and a recombinase-mediated in planta gene stacking process was described previously in tobacco based on the Mycobacteriophage Bxb1 site-specific integration system. Since this process requires a recombination site in the genome, this work describes the generation of target sites in the Japonica rice genome. Agrobacterium-mediated gene transfer yielded ~4000 random-insertion lines. Seven lines met the criteria of being single copy, not close to a centromere, not inserted within or close to a known gene or repetitive DNA, having precise recombination site sequences on both ends, and able to express the reporter gene. Each target line tested was able to accept the site-specific integration of a new gfp-containing plasmid and in three of those lines, we regenerated fertile plants. These target lines could be used as foundation lines for stacking new traits into Japonica rice.
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Affiliation(s)
- Ruyu Li
- Plant Gene Engineering Center, Chinese Academy of Sciences, Guangzhou 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Correspondence: (R.L.); (D.W.O.)
| | - Zhiguo Han
- Plant Gene Engineering Center, Chinese Academy of Sciences, Guangzhou 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Qian Yin
- Plant Gene Engineering Center, Chinese Academy of Sciences, Guangzhou 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - Meiru Li
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Mingyong Zhang
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Zhenzhen Li
- Plant Gene Engineering Center, Chinese Academy of Sciences, Guangzhou 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - Ping Wang
- Plant Gene Engineering Center, Chinese Academy of Sciences, Guangzhou 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Li Jiang
- Plant Gene Engineering Center, Chinese Academy of Sciences, Guangzhou 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - David W. Ow
- Plant Gene Engineering Center, Chinese Academy of Sciences, Guangzhou 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Correspondence: (R.L.); (D.W.O.)
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