Tyrosinase gene

Murisier, F. and Beerman, F., Genetic of pigment cells lessons from the tyrosinase gene family, Histol. HistopathoL, 21, 567, 2006. 

VII. Expression Analysis of the Tyrosinase Gene in Transgenic Mice.163... 

VII. EXPRESSION ANALYSIS OF THE TYROSINASE GENE IN TRANSGENIC MICE... 

Figure 5. Tyrosinase gene expression in melanocytes of the hair follicle. Bright field photographs show sections of skin of 4-day-old albino mice. Bar represents 50 pm.

The temporal expression pattern of the mouse tyrosinase gene during embryonic development was not known, and therefore we exploited the... 

Figure 6. Transgene and tyrosinase gene expression in early eye development. Sections are derived from embryonic day 10.5 (A, B), 12.5 (C, D), 13.5 (E), and 17.5 (F) (for details see Beermann etal., 1992a,b). Transgene-specific expression (ptrTyrS) is depicted in A, B, E, F, and tyrosinase gene expression in C and D. In A-D, the same section was photographed both in dark field (A, C) and in bright field (B, D). Bar represents 150 pm in A, B 250 pm in C, D, E and 200 pm in F.

Figure 7. Expression pattern of the mouse tyrosinase gene during embryonic development and its recapitulation in transgenic mice as determined by in situ hybridization (Beermann et al., 1992a). Black box, mouse tyrosinase open box, transgene ptrTyrf striped box, ptrTyr5. Interrupted boxes indicate variations between lines. RPE, retinal pigment epithelium e, days of gestation d0.5, newborn.

This brief summary shows that our understanding of the basis of melanocyte-specific expression of the tyrosinase gene and the tyrosinase-related genes TRP-1 and TRP-2 is still limited. Novel approaches such as the introduction of the 70-kb-long mouse tyrosinase gene with extensive 5 flanking sequences as recently achieved (Schedl et al., 1993) allow an experimental attack of this important question. 

Thanks are due to E. Hummler and A. P. Monaghan for comments on the manuscript. We also acknowledge the contributions of S. Ruppert, E. Hummler, M. KlUppel, G. Muller, A. Schmidt, and E. Schmid to the work on the mouse tyrosinase gene. The work was supported by the Deutsche Forschungsgemein-schaft (SFB 229 Leibniz Programm), the Fonds der Chemischen Industrie and the Swiss National Science Foundation. 

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Beermann, F., Schmid, E., and Schtitz, G. (1992a). Expression of the mouse tyrosinase gene during embryonic development recapitulation of the temporal regulation in transgenic mice. Proc. Natl. Acad. Sci. USA 89 2809-2813. 

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Nevertheless, some issues have to be addressed before this approach can be applied. Firstly, the tyrosinase gene is quite large and would be difficult to add to a delivery vector. Secondly, melanin production may be too low in vivo for effective MR detection of its metal complex [100]. Finally, potentially high toxicity of melanin and its precursors could restrict the applicability of this reporter gene [99]. 

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