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Evaluating Transgenic Xenopus as a Model System for the Expression of Secreted Proteins
Author(s) -
Laird Joseph G,
Marshall Katelyn R,
Dean Maria A,
Baker Sheila A
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.577.9
Subject(s) - green fluorescent protein , heterologous , xenopus , transgene , biology , microbiology and biotechnology , heterologous expression , gene , biochemistry , recombinant dna
Model systems such as E. coli, yeast, and Xenopus oocytes are frequently used to express and purify heterologous proteins for subsequent biochemical analysis. However, some vertebrate proteins, particularly those that are extensively modified, can be toxic and very difficult to purify from these systems. In this study we used GFP as a reporter to investigate the feasibility of expressing heterologous proteins from secretory tissues of transgenic X. laevis. Transgenic tadpoles were generated by restriction enzyme mediated integration. GFP was cloned under the control of the larval keratin promoter to drive expression in the epidermis and under the control of the XAG‐1 promoter to drive expression in the cement and hatching glands. GFP expression in the appropriate tissues was observed using both promoters. However, the XAG‐1 promoter caused GFP to be expressed much more uniformly and robustly. Next, we cloned a signal sequence onto GFP so that it would be secreted. The secreted GFP was assayed using Western blots and a GFP fluorescence assay. Secreted GFP was readily collected from the buffer housing either set of transgenic animals but we obtained the highest yields using animals secreting GFP from the cement and hatching glands. In conclusion, expressing proteins specifically in secretory tissues of transgenic tadpoles is a viable method to obtain heterologous proteins for subsequent biochemical analysis.