Differential expression profile of growth hormone/chorionic somatomammotropin genes in placenta of small- and large-for-gestational-age newborns.
BACKGROUND
The human growth hormone/chorionic somatomammotropin (hGH/CSH) locus at 17q22-24, consisting of one pituitary-expressed postnatal (GH1) and four placenta-expressed genes (GH2, CSH1, CSH2, and CSHL1), is implicated in regulation of postnatal and intrauterine growth. A positive correlation has been reported between the offspring's birth weight and serum placental GH (coded by GH2) and placental lactogen (coded by CSH1, CSH2) levels in pregnant women.


OBJECTIVE
The objective of the study was the investigation of the hypothesis that the mRNA expression profile of placental hGH/CSH genes contributes to the determination of birth weight.


METHODS
We developed a sensitive, fluorescent-labeled semiquantitative RT-PCR assay coupled with gene-specific restriction analysis, capable of distinguishing alternative splice-products of individual placental hGH/CSH genes and quantification of their relative expression levels. The detailed profile of alternative transcripts of GH2, CSH1, CSH2, and CSHL1 genes in placenta from uncomplicated term pregnancies of the REPROMETA sample collection was addressed in association with the birth weight of newborns, grouped as appropriate for gestational age (AGA; n = 23), small for gestational age (SGA; n = 15), and large for gestational age (LGA; n = 34).


RESULTS
The majority of pregnancies with SGA newborn showed down-regulation of the entire hGH/CSH cluster in placenta, whereas in the case of LGA, the expression of CSH1-1, CSH2-1, and CSHL1-4 mRNA transcripts in placenta was significantly increased compared with AGA newborns (P < 0.0001, P = 0.009, P = 0.002, respectively).


CONCLUSIONS
The expression profile of placental hGH/CSH genes in placenta is altered in pregnancies accompanied by SGA and LGA compared with AGA newborns, and thus, it may directly affect the circulating fetal and maternal placental GH and placental lactogen levels.
Institute of Molecular and Cell Biology, University of Tartu, Riia Street 23, 51010 Tartu, Estonia. jaana.mannik@ut.ee
Jaana
J
Männik
Pille
P
Vaas
Kristiina
K
Rull
Pille
P
Teesalu
Tiina
T
Rebane
Maris
M
Laan
D017398:Alternative Splicing; D001724:Birth Weight; D002886:Chromosomes, Human, Pair 17; D017931:DNA Primers / Q000235:genetics; D005091:Exons / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D019382:Human Growth Hormone / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D010920:Placenta / Q000502:physiology*; D010928:Placental Lactogen / Q000235:genetics*; D011247:Pregnancy; D015183:Restriction Mapping; D014158:Transcription, Genetic
D017931:DNA Primers; D019382:Human Growth Hormone; D010928:Placental Lactogen