title: Ubiquitous expression of mRFP-1 in vivo by site-directed transgenesis.
abstract: Progress in our understanding of the molecular cellular basis of immune function depends on our ability to track and image individual immune cells in vivo. To this end, the development of mouse models over-expressing various fluorescent proteins would represent an important experimental tool. In this report, we describe the generation and characterization of pUbi-mRFP-1 transgenic mice, in which the monomeric form of red fluorescent protein is ubiquitously expressed in various lymphoid and non-lymphoid tissues. Our newly generated pUbi-mRFP-1 mice are unique among previously reported mice transgenic for red fluorescent proteins because a single-copy of the mRFP-1 transgene driven by human ubiquitin C promoter has been integrated by homologous recombination into the mouse hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus. We show that the distinct and uniform levels of mRFP-1 expression allow easy identification of transferred hematopoietic cells by FACS analysis or confocal microscopy, even when the transferred population represents a very small proportion in the target organ. Also, even in long-term experiments, we have seen no evidence of rejection of transferred pUbi-mRFP-1 lymphocytes. Due to its far-red spectrum, mRFP-1 is an ideal partner for dual imaging with green fluorescent proteins. We observed a good visual separation between donor lymphocytes derived from either mRFP-1 or eGFP transgenic mice in recipient animals. Our study suggests that the new pUbi-mRFP-1 transgenic mouse strain offers new opportunities for studying cellular interactions and migratory patterns of cells, especially for dual imaging of different cell types. In summary, our results demonstrate that a controlled strategy of transgenesis provides an effective means of ubiquitously expressing fluorescent proteins in vivo.
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, H3A 2B4, Canada.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Yurchenko
authors.forename: Hanna
authors.initials: H
authors.lastname: Friedman
authors.forename: Valerie
authors.initials: V
authors.lastname: Hay
authors.forename: Alan
authors.initials: A
authors.lastname: Peterson
authors.forename: Ciriaco A
authors.initials: CA
authors.lastname: Piccirillo
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D005260:Female; D015870:Gene Expression; D066298:In Vitro Techniques; D007962:Leukocytes / Q000145:classification / Q000276:immunology / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics*; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D011994:Recombinant Proteins / Q000235:genetics; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism; D000097573:Red Fluorescent Protein
chemical_list: D017931:DNA Primers; D008164:Luminescent Proteins; D011994:Recombinant Proteins; D000097573:Red Fluorescent Protein