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Unformatted text preview: that Agrp might
play an important role in regulating body weight. Human AGRP produces obesity when overexpressed in mice by means of a transgene
(Fig. 3)23. Transgenic animals, in which expression of human AGRP
is placed under control of the ubiquitously expressed -actin promoter, weigh twice as much as their non-transgenic littermates by
three months of age. Overexpression of human Agouti by means of a
similar -actin transgene produces a similar weight phenotype23.
However, the ubiquitous expression of the agouti gene (Fig. 1) produces yellow animals whereas the ubiquitous expression of AGRP 15 ment
Fig. 1. Melanocyte development. A: Melanoblasts, the precursors to melanocytes, arise from the
neural crest and then migrate to their destination, e.g., in the hair follicle. Several genes known to
affect the development of melanoblasts and melanocytes are indicated. B: When in the hair follicle,
the melanoblasts either go straight to the hair follicle matrix and form fully developed melanocytes
or they go to the bulge region where they form melanocyte stem cells. During each hair cycle, the
melanocyte stem cel...
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- Fall '14