Cloning of four growth hormone/chorionic somatomammotropin-related complementary deoxyribonucleic acids differentially expressed during pregnancy in the rhesus monkey placenta.

Abstract

The close homology of the chorionic somatomammotropin (CS) genes with pituitary GH is unique to primates. Southern blots of rhesus genomic DNA probed with a human CS cDNA demonstrated that the rhesus gene family consists of at least five EcoRI fragments between 2.3-9.5 kilobases. Rhesus pituitary and placental cDNA libraries were screened for hCS-hybridizing clones. A pituitary GH cDNA was isolated that was 95% and 96% identical to human GH at the mRNA and protein levels, respectively. Thirteen placental clones representing four different cDNAs were identified and sequenced. The relationships of the rhesus placental clones among themselves were similar to those among human placental mRNAs. Two cDNAs (mCS1 and mCS2) differed by two bases and coded for identical proteins. A third cDNA (mCS3) was 94% homologous to mCS1/2 in mRNA sequence as well as in deduced amino acid sequence. A fourth cDNA (mGH-V) was 84-86% homologous to the other placental cDNAs at the mRNA and protein levels, similar to the homology between human placental GH-V and CS mRNAs. To determine the relative expression of placental mRNAs, we developed a quantitative reverse transcription-polymerase chain reaction assay using diagnostic NlaIV restriction enzyme sites in cDNAs amplified from the placental mRNAs. All four mRNAs were expressed in the placenta throughout most of pregnancy, with the mCS1 and mGH-V mRNAs generally expressed at 2- to 10-fold higher levels than mCS2 and mCS3. Additionally, mCS3 and mGHV were expressed at relatively higher levels during the second and third trimesters than during the first trimester.

Episodic evolution of prolactin receptor gene in mammals: coevolution with its ligand

“…Thus, clusters of PRL-like genes are found in rodents and ruminants (Forsyth & Wallis 2002) and a cluster of growth hormone-like genes is found in higher primates (Chen et al 1989, Golos et al 1993, Wallis et al 2001. Most other mammalian groups, including pig, rabbit and dog, do not appear to have such a cluster (Talamantes et al 1980, Forsyth & Wallis 2002, and in the case of dog this was confirmed by a BLAST search of the genome sequence.…”

“…Most other mammalian groups, including pig, rabbit and dog, do not appear to have such a cluster (Talamantes et al 1980, Forsyth & Wallis 2002, and in the case of dog this was confirmed by a BLAST search of the genome sequence. Placental lactogens appear to use the PRLR signaling pathway (Golos et al 1993, Soares et al 1998, Herman et al 2000, Biener et al 2003 like pituitary PRL. This might suggest that the episodic evolution observed for the PRLR reflects adaptation to the presence of multiple ligands.…”

Independent origin of the growth hormone gene family in New World monkeys and Old World monkeys/hominoids

“…Most mammals and lower primates, such as the bush baby and the slow loris, have only a single copy of the GH gene in their genomes , Wallis et al 2001, while, as the result of a series of gene duplications, a cluster of GH-like genes has been observed in the marmoset, spider monkey, rhesus monkey and man (Chen et al 1989, Golos et al 1993, Wallis et al 2001, Wallis & Wallis 2002, Mendoza et al 2004. Humans have five GH-related genes, all located in chromosome 17q22-24 (George et al 1981).…”

“…Functional members of the hGH/hCSH family have 191 amino-acid residues encoded by five exons, and the sequence similarity among members reaches more than 90% at the DNA level (Chen et al 1989). In the rhesus monkey, one pituitary-expressed GH gene and four placentaexpressed genes have been reported (Golos et al 1993). However, in the marmoset (a NWM), all the GH-like genes cluster together in the phylogenetic tree, and none cluster with any GH-like gene of human or rhesus monkey, indicating that the gene duplications that gave rise to the marmoset GH-like gene cluster were independent of those of man and rhesus monkey (Wallis & Wallis 2002).…”

Cloning and characterisation of the gene encoding mole rat (Spalax ehrenbergi) growth hormone

“…The rat gene differs from that of other mammals, including mouse, in that the second intron includes a repetitive sequence of approximately 500 bp (Barta et al 1981). Rats and mice, like most other non-primate mammals, contain a single GH gene, with no evidence for duplicate or multiple genes for GH-like proteins as is found in goat and sheep (Valinsky et al 1990) and higher primates (Chen et al 1989, Golos et al 1993. In man the GH-like proteins include placental lactogens, but in rodents and ruminants placental lactogens are prolactin-like (Wallis 1992).…”