Multiple forms of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase are expressed in perinatal rat liver.
Fetal rat liver expresses a 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/Fru-2,6-Pase2) form that differs from the adult liver enzyme in the inhibition by phosphorylation by the adenosine 3',5'-cyclic monophosphate-dependent protein kinase and in the recognition by an antibody specific for the NH2-terminal domain of the adult liver enzyme. Northern blot analysis shows that fetal hepatocytes contain a species of mRNA that is 2.2 kb in size and that exhibits the maximal levels after delivery. PFK-2/Fru-2,6-Pase2 mRNA analysis using a sensitive ribonuclease protection assay reveals the presence of nearly similar amounts of adult liver-specific and skeletal muscle-specific mRNA in fetal liver and hepatocytes during the last days of gestation, as well as a 233-bp protected fragment present in fetal liver. These results were confirmed by polymerase chain reaction using specific oligonucleotide pairs. Primer extension of fetal liver cDNA suggests the presence of two initiation sites of transcription. Analysis of the adult liver PFK-2/Fru-2,6-Pase2 protein during the perinatal transition using a specific antibody shows a marked accumulation of this form immediately after birth.
Casado
M
M
Facultad de Farmacia, Instituto de Bioquímica, Consejo Superior de Investigaciones Científicas-Universidad Complutense, Madrid, Spain.
Boscá
L
L
Martín-Sanz
P
P
D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D005333:Fetus / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000196:embryology / Q000201:enzymology*; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes / Q000235:genetics; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014158:Transcription, Genetic
D007527:Isoenzymes; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D017853:Phosphotransferases (Alcohol Group Acceptor); D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases