Cloning the chicken leptin gene

Taouis, Mohammed; Chen, Jinwen; Daviaud, Christian; Dupont, Joëlle; Derouet, Michel; Simon, Jean

doi:10.1016/s0378-1119(97)00670-7

Cited by 184 publications

(116 citation statements)

References 15 publications

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“…Using quantitative RT-PCR (RTqPCR), we found leptin mRNA in diverse frog tissues, including fat and liver, where leptin is primarily expressed in mammals and chicken (1,21), but also in brain, pituitary gland, heart, gastrointestinal tract, lungs, kidney, and gonads (Fig. 3A); we obtained similar results with semiquantitative RT-PCR (data not shown).…”

Section: Resultssupporting

confidence: 61%

“…The predicted leptin protein of X. laevis shares Յ35% sequence similarity with mammalian leptins, which is in striking contrast to the 95% sequence similarity reported between the mouse and chicken ob genes (greater similarity than that among several mammalian leptins) (21,23). Despite the low sequence similarities between the ectotherm and mammalian leptins, molecular modeling shows a conserved four-helix structure that is not only characteristic of mammalian leptins but also of other long-chain helical cytokines (24).…”

Section: Discussionmentioning

confidence: 60%

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

Crespi

Denver

2006

Proc. Natl. Acad. Sci. U.S.A.

148

133

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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 (Ϸ35%) 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.evolution ͉ metamorphosis ͉ obesity T he protein hormone leptin is a type-I cytokine secreted by adipocytes that acts on the CNS to regulate food intake and metabolism (1, 2). In addition to the regulation of body weight, leptin influences reproduction, growth, stress responses, and thyroid function (3, 4). Actions of leptin are both acute and chronic. For example, postprandial increases in plasma leptin inhibit food intake, whereas daily mean plasma leptin concentrations communicate long-term energy status to the brain (5). These actions are mediated by membrane leptin receptors (LRs), of which six isoforms have been identified in mammals (6). Leptin binding to the long form of the LR (LRb) activates the Janus kinase 2͞signal transducer and activator of transcription 3 (STAT-3) signaling pathway (7), which mediates leptin effects on food intake, glucose metabolism, and weight gain but does not affect fertility (8).The rising prevalence of human obesity and metabolic disorders (9) has focused research on the physiological role of leptin in energy balance and food intake in adult mammals. Recently, links between birth weight and adult-onset metabolic disorders (10) has turned attention to possible relationships among leptin, growth, and development during fetal stages. Circulating leptin is elevated in the human fetus during late gestation and correlates with fat mass and birth weight (11,12). In the fetal mouse, leptin and LR are expressed in liver, heart, hair follicles, and primordial bone before the formation of adipose tissue (13,14), and leptin is found in the circulation of fetal sheep (15)...

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Section: Resultssupporting

confidence: 61%

Section: Discussionmentioning

confidence: 60%

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

Crespi

Denver

2006

Proc. Natl. Acad. Sci. U.S.A.

148

133

View full text Add to dashboard Cite

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“…Also, the location of the bridge as determined through x-ray crystallography is in close proximity to the N-terminus [26] where our unpaired cysteine is located. In chicken an unpaired cysteine is found 3 amino acids from the N-terminus of the mature leptin protein [31]. Dridi et al [4] substituted this cysteine with a serine and suggested that it does not alter bioactivity.…”

Section: Discussionmentioning

confidence: 99%

Association of a missense mutation in the bovine leptin gene with carcass fat content and leptin mRNA levels

et al. 2002

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-Previously, we have shown that alleles of the BM1500 microsatellite, located 3.6 kb downstream of the leptin gene in cattle, were associated with carcass fat measures in a population of 154 unrelated beef bulls. Subsequently, a cytosine (C) to thymine (T) transition that encoded an amino acid change of an arginine to a cysteine was identified in exon 2 of the leptin gene. A PCR-RFLP was designed and allele frequencies in four beef breeds were correlated with levels of carcass fat. The T allele was associated with fatter carcasses and the C allele with leaner carcasses. The frequencies of the SNP alleles among breeds indicated that British breeds have a higher frequency of the T allele whereas the continental breeds have a higher occurrence of the C allele. A ribonuclease protection assay was developed to quantify leptin mRNA in a separate group of animals selected by genotype. Animals homozygous for thymine expressed higher levels of leptin mRNA. This may suggest that the T allele, which adds an extra cysteine to the protein, imparts a partial loss of biological function and hence could be the causative mutation.leptin / cattle / obese / fat / marbling

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“…4d). While relative leptin expression in chickens has been shown to be higher in liver than adipose tissue [4,5], immunohistochemical staining of leptin in hepatic cytoplasm was diffuse and light as compared to adipocytes (compare Fig. 4c,d).…”

Section: Resultsmentioning

confidence: 85%

“…In mammals, leptin is expressed primarily in white adipose tissue, although other tissues such as gastric epithelial lining, placenta, muscle, brain, pituitary, and hypothalamus have also been found to be sites of leptin expression [1]. In chickens, leptin is produced by liver and adipose tissue, with liver being the predominant site of expression [4,5]. Leptin has been reported to function in the regulation of appetite, energy metabolism, fertility, and in the maintenance of body weight by acting as a peripheral hormone 'sensor' for the size of adipocyte energy (lipid) stores [6].…”

Section: Introductionmentioning

confidence: 99%

Design and application of a polyclonal peptide antiserum for the universal detection of leptin protein

Richards

Caperna

Elsasser

et al. 2000

Journal of Biochemical and Biophysical Methods

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Richards, Mark P.; Caperna, Thomas J.; Elasser, Theodore H.; Ashwell, Christopher M.; and McMurtry, John P., "Design and application of a polyclonal peptide antiserum for the universal detection of leptin protein" (2000). AbstractAn epitope-specific polyclonal antiserum was produced in rabbits immunized against a synthetic 15 amino acid peptide (QRVTGLDFIPGLHPV) derived from the coding sequence reported for the porcine leptin gene (GenBank Accession No. U59894). This peptide contains a core sequence comprised of eight amino acids (GLDFIPGL) that is totally conserved in all leptin proteins studied to date. Purified recombinant human, mouse, rat, pig, and chicken leptin proteins were separated by polyacrylamide gel electrophoresis (SDS-PAGE) and electro-blotted onto PVDF membranes. Western blots were developed employing the leptin-specific peptide antiserum with an alkaline-phosphatase-conjugated anti-rabbit IgG second antibody chromogenic system. The peptide antiserum was found to be highly specific for leptin which exhibited an estimated molecular weight of about 16 kDa for all species analyzed. The sensitivity of the Western blot assay was not sufficient to permit the direct detection of leptin in chicken serum or plasma. However, with this assay we were able to detect native leptin protein in an enriched fraction prepared from chicken plasma using a combination of gel filtration and ion exchange column chromatography. Slot blots indicated a potential application of the immunostaining technique for quantitative analysis of leptin protein. Finally, the peptide antiserum was successfully employed to localize leptin protein by immunohistochemical staining of thin sections prepared from adipose (chicken and pig) and liver (chicken) tissue samples. This study is the first to report a polyclonal peptide antiserum that apparently recognizes intact leptin protein, both native and recombinant, regardless of the species of origin.

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Cloning the chicken leptin gene

Cited by 184 publications

References 15 publications

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

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

Association of a missense mutation in the bovine leptin gene with carcass fat content and leptin mRNA levels

Design and application of a polyclonal peptide antiserum for the universal detection of leptin protein

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