Expression of Ras GTPase-activating protein (GAP) in human normal chorionic villi and hydatidiform mole.
Ras GTPase-activating protein (GAP), an important downregulator of Ras activity, has previously been shown to be abundant in human placenta. The expression of p120 and p100 isoforms of GAP in human normal chorionic villi (n=5) and hydatidiform mole (n=5) was investigated to clarify the involvement of Ras GAP in the growth of chorionic villi in the first trimester of pregnancy. Immunoblot analysis revealed that both p120- and p100-GAP isoforms were remarkably less expressed in mole villi than in normal chorionic villi. The expression of p100-GAP significantly reduced in comparison with that of pl20-GAP in mole villi. Northern blot analysis showed that the amount of GAP mRNA reduced in hydatidiform mole less than one-third of that in normal chorionic villi. The GAP activity, measured by the effect of tissue extract on the hydrolysis of Ras-bound GTP, was significantly lower in hydatidiform mole than in normal chorionic villi. These results suggest that Ras GAP may play an important role in the normal growth and differentiation of human chorionic villi in the first trimester.
Sasa
H
H
Department of Perinatal and Maternal Medicine, National Defense Medical College, Tokorozawa, Saitama, Japan.
Umekage
T
T
Namima
M
M
Arimura
S
S
Nakata
H
H
Watanabe
Y
Y
Kobayashi
M
M
D000818:Animals; D015152:Blotting, Northern; D002824:Chorionic Villi / Q000378:metabolism*; D005260:Female; D020690:GTPase-Activating Proteins; D006801:Humans; D006828:Hydatidiform Mole / Q000378:metabolism; D015151:Immunoblotting; D011247:Pregnancy; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D014594:Uterine Neoplasms / Q000378:metabolism*; D020703:ras GTPase-Activating Proteins
D020690:GTPase-Activating Proteins; D012333:RNA, Messenger; D020703:ras GTPase-Activating Proteins