The human obese (OB) gene: RNA expression pattern and mapping on the physical, cytogenetic, and genetic maps of chromosome 7.

Abstract

The recently identified mouse obese (ob) gene apparently encodes a secreted protein that may function in the signaling pathway of adipose tissue. Mutations in the mouse ob gene are associated with the early development of gross obesity. A detailed knowledge concerning the RNA expression pattern and precise genomic location of the human homolog, the OB gene, would facilitate examination of the role of this gene in the inheritance of human obesity. Northern blot analysis revealed that OB RNA is present at a high level in adipose tissue but at much lower levels in placenta and heart. OB RNA is undetectable in a wide range of other tissues. Comparative mapping of mouse and human DNA indicated that the ob gene is located within a region of mouse chromosome 6 that is homologous to a portion of human chromosome 7q. We mapped the human OB gene on a yeast artificial chromosome (YAC) contig from chromosome 7q31.3 that contains 43 clones and 19 sequence-tagged sites (STSs). Among the 19 STSs are eight corresponding to microsatellite-type genetic markers, including seven (CA)n repeat-type Genethon markers. Because of their close physical proximity to the human OB gene, these eight genetic markers represent valuable tools for analyzing families with evidence of hereditary obesity and for investigating the possible association between OB mutations and human obesity.

Placental Leptin: An Important New Growth Factor in Intrauterine and Neonatal Development?

“…The placenta was found to express leptin mRNA at comparable or greater levels than adipose tissue. Green et al 21 using Northern blot analysis, also found leptin mRNA in polyAϩ RNA from placental tissue but at a lower level than in total RNA from adipose tissue. It is possible that a comparison of leptin expression from total RNA of fat tissue to that of polyAϩ RNA from placenta underestimated placental tissue as a major source of leptin production.…”

The Effects of 3000 Meters Swimming on Serum Level of Leptin and Glucose Under 2 Different Intensities: Continuous and Intermittent

“…Leptin, a product of Ob gene, is a newly discovered single-chain prohormone with the molecular mass of 16 kDa, which seems to play a key role in regulating body weight (1). Leptin is produced by various adipose tissues, although other tissues like fundus of the stomach, skeletal muscles, liver, placenta (2), heart (3), cumulus oophorus and granular cells of human ovary, mammary gland (4), and epithelial cells of the stomach (5) produce it too.…”

Analyse génotypique de gènes de susceptibilité à l'obésité au sein d'une cohorte de travailleurs forestiers de la compagnie Abitibi Consolotidated de Saint-Félicien /

“…La localisation de son équivalent chez l'humain fut réalisée en 1995 (Green et al, 1995) et en se basant sur les observations faites sur les rongeurs, on posait l'hypothèse que l'obésité chez l'humain pouvait résulter d'une déficience relative ou complète en leptine. Par ailleurs, pour la majorité des sujets obèses, on est rapidement venu à la conclusion que le rôle de la leptine chez l'humain ne semblait pas aussi important que chez la souris.…”