Gene expression of human pregnancy-associated plasma protein-A in placenta from trisomic pregnancies.
Placental pregnancy-associated plasma protein-A (PAPP-A) mRNA expression, placental PAPP-A protein concentration and maternal serum levels of PAPP-A were examined in pregnancies affected by trisomy 21 (n=8), trisomy 18 (n=7) and 15 normal controls at 12-15 weeks of gestation. The maternal serum concentration of PAPP-A in the trisomic group of pregnancies was significantly lower than in the normal controls. However there were no significant differences between the three groups in PAPP-A mRNA expression or PAPP-A protein concentration in the placental tissues. There was no significant association between the level of placental mRNA and either placental protein or maternal serum PAPP-A concentrations in the normal or trisomic pregnancies. There was however a significant association between placental protein and maternal serum PAPP-A concentrations in the normal and trisomy 21 pregnancies but not in those affected by trisomy 18. These findings suggest that the decrease in maternal serum PAPP-A in trisomic pregnancies is due to alternations in post-translational events such as protein stability, alterations in the release mechanism of the protein, impaired protein transport across the placenta or modified serum stability of PAPP-A.
Brizot
M L
ML
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London.
Hyett
J A
JA
Mckie
A T
AT
Bersinger
N A
NA
Farzaneh
F
F
Nicolaides
K H
KH
D002887:Chromosomes, Human, Pair 18; D004314:Down Syndrome / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011266:Pregnancy-Associated Plasma Protein-A / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D014314:Trisomy
D012333:RNA, Messenger; D011266:Pregnancy-Associated Plasma Protein-A