Growth hormone-related genes from baboon (Papio hamadryas): Characterization, placental expression and evolutionary aspects
详细信息 查看全文
- 作者：Irá ; m Pablo Rodrí ; guez-Sá ; nchez ; Maria Elizabeth Tejero ; Shelley A. Cole ; Anthony G. Comuzzie ; Peter W. Nathanielsz ; Michael Wallis ; Hugo A. Barrera-Saldañ ; a
- 关键词：Primates ; Pregnancy ; GH locus ; Chorionic somatomammotropin hormone ; Molecular evolution ; Alternative splicing
- 刊名：Gene
- 出版年：2010
- 出版时间：15 January 2010
- 年：2010
- 卷：450
- 期：1-2
- 页码：1-7
- 全文大小：645 K
文摘
Pregnancy is a complex physiological condition, and the growth hormone (GH)-related hormones produced in the placenta, which emerged during the evolution of primates, are thought to play an important metabolic role in pregnancy that is not yet fully understood. The aim of this study was to identify the genes and transcription products of the GH family in baboon (Papio hamadryas) and to assess these in relation to the evolution of this gene family. GH-related transcripts were amplified using total RNA from placental tissue, by reverse transcription coupled to polymerase chain reaction (RT-PCR). Three different GH-related transcripts were identified in baboon placental tissue, with two encoding chorionic somatomammotropins (CSH) and one the placental variant of GH (GH-2). The CSH transcripts showed some minor allelic variation, and a splice variant of CSH-C that retains its in-frame third intron. Gene sequences for GH-1 (probably representing the GH gene expressed primarily in the pituitary gland), GH-2 and the two CSHs were identified in the baboon genomic database, together with a CSH-related pseudogene. Phylogenetic analysis of the baboon GH-related sequences, together with those of a related Old World monkey, macaque, and ape outgroup (human), showed the equivalence of the genes in baboon and macaque, and revealed evidence for several episodes of rapid adaptive evolution. Many of the substitutions seen during the evolution of these placental proteins have occurred in the receptor-binding sites, especially site 2, contrasting with the strong conservation of the hydrophobic core.