Leptin (ob gene) of the South African clawed frog Xenopus laevis

Erica J Crespi; Robert J Denver

doi:10.1073/pnas.0507519103

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Leptin (ob gene) of the South African clawed frog Xenopus laevis

Journal article

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Leptin (ob gene) of the South African clawed frog Xenopus laevis

Erica J Crespi and Robert J Denver

Proceedings of the National Academy of Sciences - PNAS, Vol.103(26), pp.10092-10097

06/27/2006

DOI: https://doi.org/10.1073/pnas.0507519103

Handle:

https://hdl.handle.net/2376/114919

PMCID: PMC1502511

PMID: 16782821

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Abstract

Biological Sciences

evolution

metamorphosis

obesity

Leptin, the protein product of the obese ( ob ) gene, is a type-I cytokine hormone secreted by fat that is integral to food intake regulation and influences almost every physiological system in juvenile and adult mammals. Since the identification of leptin in the mouse in 1994, biologists have searched for orthologous genes in other species with limited success. In this article, we report the identification and functional characterization of leptin and leptin receptor (LR) in Xenopus . Despite low amino acid sequence similarity to mammalian leptins (≈35%) the frog protein has a nearly identical predicted tertiary structure and can activate the frog and mouse LRs in vitro . We showed that recombinant frog leptin (rxLeptin) is a potent anorexigen in frogs, as it is in mammals, but this response does not develop until midprometamorphosis. However, during early prometamorphosis, exogenous rxLeptin induced growth and development of the hind limb, where LR mRNA is expressed. The rxLeptin also stimulated cell proliferation in cultured hind limbs from early prometamorphic tadpoles, as measured by [ 3 H]thymidine uptake. These findings are evidence that leptin can influence limb growth and differentiation during early development. Furthermore, the isolation and characterization of leptin and its receptor in a nonamniote provides an essential foundation for elucidating the structural and functional evolution of this important hormone.

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Title: Leptin (ob gene) of the South African clawed frog Xenopus laevis
Creators: Erica J Crespi - Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 North University Avenue, Ann Arbor, MI 48109-1048
Robert J Denver - Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 North University Avenue, Ann Arbor, MI 48109-1048
Publication Details: Proceedings of the National Academy of Sciences - PNAS, Vol.103(26), pp.10092-10097
Academic Unit: Biological Sciences, School of
Publisher: National Academy of Sciences
Identifiers: 99900548125601842
Language: English
Resource Type: Journal article