Evolution of the Vertebrate Resistin Gene Family
PLOS ONE
Authors: Hu, Qingda; Tan, Huanran; Irwin, David M.
Abstract
Resistin (encoded by Retn) was previously identified in rodents as a hormone associated with diabetes; however human resistin is instead linked to inflammation. Resistin is a member of a small gene family that includes the resistin-like peptides (encoded by Retnl genes) in mammals. Genomic searches of available genome sequences of diverse vertebrates and phylogenetic analyses were conducted to determine the size and origin of the resistin-like gene family. Genes encoding peptides similar to resistin were found in Mammalia, Sauria, Amphibia, and Actinistia (coelacanth, a lobe-finned fish), but not in Aves or fish from Actinopterygii, Chondrichthyes, or Agnatha. Retnl originated by duplication and transposition from Retn on the early mammalian lineage after divergence of the platypus, but before the placental and marsupial mammal divergence. The resistin-like gene family illustrates an instance where the locus of origin of duplicated genes can be identified, with Retn continuing to reside at this location. Mammalian species typically have a single copy Retn gene, but are much more variable in their numbers of Retnl genes, ranging from 0 to 9. Since Retn is located at the locus of origin, thus likely retained the ancestral expression pattern, largely maintained its copy number, and did not display accelerated evolution, we suggest that it is more likely to have maintained an ancestral function, while Retnl, which transposed to a new location, displays accelerated evolution, and shows greater variability in gene number, including gene loss, likely evolved new, but potentially lineage-specific, functions.
The contributions of resistin and adiponectin gene single nucleotide polymorphisms to the genetic risk for polycystic ovary syndrome in a Japanese population
GYNECOLOGICAL ENDOCRINOLOGY
Authors: Baba, Tsuyoshi; Endo, Toshiaki; Sata, Fumihiro; Nagasawa, Kunihiko; Honnma, Hiroyuki; Kitajima, Yoshimitsu; Hayashi, Takuhiro; Manase, Kengo; Kanaya, Mika; Moriwaka, Osamu; Kamiya, Hirofumi; Yamada, Hideto; Minakami, Hisanori; Kishi, Reiko; Saito, Tsuyoshi
Abstract
Polycystic ovary syndrome (PCOS) is a heterogeneous group of disorders that occur fairly commonly in women of reproductive age and are characterized by a variety of clinical manifestations, including insulin resistance that is independent of obesity. Recent studies suggest that altered adipocytokine gene expression is closely associated with insulin resistance and that single nucleotide polymorphisms (SNPs) modulate the expression and/or function of these genes, thereby affecting insulin sensitivity. With that in mind, we investigated whether SNPs at position 7420 of the resistin gene (RETN) and/or 711377 of the adiponectin gene (ADIPOQ) modulate the susceptibility to PCOS. We evaluated the genotypes of 117 women with PCOS and 380 healthy fertile controls and measured the index of insulin resistance and hormonal profiles in the PCOS women. The RETN 7420G/G homozygous variant genotype occurred significantly more frequently among the PCOS group than among the control group (15.4% vs. 8.4%, p = 0.035). PCOS women with the RETN 7420G/ G genotype also showed significantly higher BMIs and greater insulin resistance than those with RETN 7420 C/C or C/G genotypes. The ADIPOQ SNP at 711377 showed no association with PCOS. We conclude that the RETN G/G at 7420 genotype is associated with PCOS in Japanese women.