Faculty Opinions recommendation of Transgenic mouse line with green-fluorescent protein-labeled Centrin 2 allows visualization of the centrosome in living cells.

Author(s):  
Stephen Doxsey
2007 ◽  
Vol 19 (8) ◽  
pp. 984 ◽  
Author(s):  
Anna Mayer ◽  
Diana Bulian ◽  
Hagen Scherb ◽  
Martin Hrabé de Angelis ◽  
Jörg Schmidt ◽  
...  

Certain transgenic mouse lines are difficult to breed or archive and, consequently, their transgenes become lost. We examined a C57BL/6 mouse line (B6-tg), transgenic for green fluorescent protein (GFP) with low fertility, and its crosses with the more prolific inbred C3HeB/FeJ (C3) and outbred Swiss (SW) strains in order to assess the possibility of emergency prevention of extinction of a transgenic allele by using assisted reproductive technologies (ART). Out-crossing was performed by natural mating or in vitro fertilisation (IVF) with heterozygous mice. Most of the crossing combinations resulted in improved archiving and rederivation efficiencies of the transgenic allele. Natural crossing increased both mean litter size by two to three pups and the superovulatory rate from 69% for B6-tg to 70–90% for females from the out-crosses. Each plug-positive B6-tg female yielded an average of 4.6 two-cell embryos, whereas females from the out-crosses produced three- to fivefold that amount. After thawing, 13% of B6-tg embryos and 6–12% of out-crossed embryos developed into transgenic pups after transfer into recipients. After IVF with cryopreserved spermatozoa, cleavage rates were 4% for B6-tg, 22–37% for B6-tg oocytes out-crossed with C3 and SW spermatozoa, 9–49% for gametes from out-crossed mice and 28–44% for back-crosses with B6 oocytes. Transgenic pups were not derived from IVF with B6-tg gametes when either fresh or cryopreserved spermatozoa were used. Rederivation efficiencies were 7% and 4% from out-crosses of B6-tg oocytes with C3 and SW spermatozoa, respectively, 6–22% for gametes from out-crossed mice and 4–10% for the back-crosses. Although out-crossing changes the original genetic background, the strategy of crossing coupled with ART prevents the extinction of an allele of interest, especially where archiving and rederivation of the transgenic line fail.


Function ◽  
2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Nelly Redolfi ◽  
Elisa Greotti ◽  
Giulia Zanetti ◽  
Tino Hochepied ◽  
Cristina Fasolato ◽  
...  

AbstractMitochondria play a key role in cellular calcium (Ca2+) homeostasis. Dysfunction in the organelle Ca2+ handling appears to be involved in several pathological conditions, ranging from neurodegenerative diseases, cardiac failure and malignant transformation. In the past years, several targeted green fluorescent protein (GFP)-based genetically encoded Ca2+ indicators (GECIs) have been developed to study Ca2+ dynamics inside mitochondria of living cells. Surprisingly, while there is a number of transgenic mice expressing different types of cytosolic GECIs, few examples are available expressing mitochondria-localized GECIs, and none of them exhibits adequate spatial resolution. Here we report the generation and characterization of a transgenic mouse line (hereafter called mt-Cam) for the controlled expression of a mitochondria-targeted, Förster resonance energy transfer (FRET)-based Cameleon, 4mtD3cpv. To achieve this goal, we engineered the mouse ROSA26 genomic locus by inserting the optimized sequence of 4mtD3cpv, preceded by a loxP-STOP-loxP sequence. The probe can be readily expressed in a tissue-specific manner upon Cre recombinase-mediated excision, obtainable with a single cross. Upon ubiquitous Cre expression, the Cameleon is specifically localized in the mitochondrial matrix of cells in all the organs and tissues analyzed, from embryos to aged animals. Ca2+ imaging experiments performed in vitro and ex vivo in brain slices confirmed the functionality of the probe in isolated cells and live tissues. This new transgenic mouse line allows the study of mitochondrial Ca2+ dynamics in different tissues with no invasive intervention (such as viral infection or electroporation), potentially allowing simple calibration of the fluorescent signals in terms of mitochondrial Ca2+ concentration ([Ca2+]).


PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0129934 ◽  
Author(s):  
Stefanie Besser ◽  
Marit Sicker ◽  
Grit Marx ◽  
Ulrike Winkler ◽  
Volker Eulenburg ◽  
...  

1997 ◽  
Vol 139 (6) ◽  
pp. 1465-1476 ◽  
Author(s):  
Norio Sakai ◽  
Keiko Sasaki ◽  
Natsu Ikegaki ◽  
Yasuhito Shirai ◽  
Yoshitaka Ono ◽  
...  

We expressed the γ-subspecies of protein kinase C (γ-PKC) fused with green fluorescent protein (GFP) in various cell lines and observed the movement of this fusion protein in living cells under a confocal laser scanning fluorescent microscope. γ-PKC–GFP fusion protein had enzymological properties very similar to that of native γ-PKC. The fluorescence of γ-PKC– GFP was observed throughout the cytoplasm in transiently transfected COS-7 cells. Stimulation by an active phorbol ester (12-O-tetradecanoylphorbol 13-acetate [TPA]) but not by an inactive phorbol ester (4α-phorbol 12, 13-didecanoate) induced a significant translocation of γ-PKC–GFP from cytoplasm to the plasma membrane. A23187, a Ca2+ ionophore, induced a more rapid translocation of γ-PKC–GFP than TPA. The A23187-induced translocation was abolished by elimination of extracellular and intracellular Ca2+. TPA- induced translocation of γ-PKC–GFP was unidirected, while Ca2+ ionophore–induced translocation was reversible; that is, γ-PKC–GFP translocated to the membrane returned to the cytosol and finally accumulated as patchy dots on the plasma membrane. To investigate the significance of C1 and C2 domains of γ-PKC in translocation, we expressed mutant γ-PKC–GFP fusion protein in which the two cysteine rich regions in the C1 region were disrupted (designated as BS 238) or the C2 region was deleted (BS 239). BS 238 mutant was translocated by Ca2+ ionophore but not by TPA. In contrast, BS 239 mutant was translocated by TPA but not by Ca2+ ionophore. To examine the translocation of γ-PKC–GFP under physiological conditions, we expressed it in NG-108 cells, N-methyl-d-aspartate (NMDA) receptor–transfected COS-7 cells, or CHO cells expressing metabotropic glutamate receptor 1 (CHO/mGluR1 cells). In NG-108 cells , K+ depolarization induced rapid translocation of γ-PKC–GFP. In NMDA receptor–transfected COS-7 cells, application of NMDA plus glycine also translocated γ-PKC–GFP. Furthermore, rapid translocation and sequential retranslocation of γ-PKC–GFP were observed in CHO/ mGluR1 cells on stimulation with the receptor. Neither cytochalasin D nor colchicine affected the translocation of γ-PKC–GFP, indicating that translocation of γ-PKC was independent of actin and microtubule. γ-PKC–GFP fusion protein is a useful tool for investigating the molecular mechanism of γ-PKC translocation and the role of γ-PKC in the central nervous system.


2000 ◽  
Vol 113 (15) ◽  
pp. 2679-2683 ◽  
Author(s):  
K. Sugaya ◽  
M. Vigneron ◽  
P.R. Cook

RNA polymerase II is a multi-subunit enzyme responsible for transcription of most eukaryotic genes. It associates with other complexes to form enormous multifunctional ‘holoenzymes’ involved in splicing and polyadenylation. We wished to study these different complexes in living cells, so we generated cell lines expressing the largest, catalytic, subunit of the polymerase tagged with the green fluorescent protein. The tagged enzyme complements a deficiency in tsTM4 cells that have a temperature-sensitive mutation in the largest subunit. Some of the tagged subunit is incorporated into engaged transcription complexes like the wild-type protein; it both resists extraction with sarkosyl and is hyperphosphorylated at its C terminus. Remarkably, subunits bearing such a tag can be incorporated into the active enzyme, despite the size and complexity of the polymerizing complex. Therefore, these cells should prove useful in the analysis of the dynamics of transcription in living cells.


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