Purification and cDNA cloning of a transcription factor which functionally cooperates within a cAMP regulatory unit in the porcine uPA gene.
One of cAMP-regulatory sites in the porcine urokinase-type plasminogen activator (uPA) gene resides 3.4 kb upstream of the transcription initiation site and is composed of three protein binding domains, FPA, FPB and FPC. Whereas FPA and FPB contain a CRE-like sequence, the FPC sequence is not related to any known protein recognition sequences, yet all three domains are required to mediate cAMP action on a heterologous promoter. To study the functional cooperation among these three domains we purified and cloned a FPC-binding protein (FPCB) from porcine kidney derived LLC-PK1 cells. Sequence comparisons showed that FPCB is homologous to mouse LFB3 and rat vHNF1. LFB3/vHNF1 is related to a liver specific transcription factor HNF1, it recognizes the same sequence as HNF1 and is highly expressed in kidney cells. FPCB and HNF1 recognition sequences are dissimilar, nevertheless both sequences are recognized by in vitro-translated LFB3 and FPCB, indicating that binding to the two different sequences is an intrinsic character of FPCB/LFB3/vHNF1. In HeLa cells, this cAMP-responsive site was inactive whether FPCB was overexpressed or not, suggesting a requirement for an additional cell-specific factor. These results may suggest a mechanism by which hormonal control is integrated into cell-specific gene regulation.
Friedrich Miescher-Institut, Basel, Switzerland.
P A
PA
Menoud
R
R
Matthies
J
J
Hofsteenge
Y
Y
Nagamine
D051696:Activating Transcription Factors; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001798:Blood Proteins / Q000378:metabolism; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004247:DNA; D004268:DNA-Binding Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D012045:Regulatory Sequences, Nucleic Acid; D013552:Swine; D014157:Transcription Factors / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics*
D051696:Activating Transcription Factors; D001798:Blood Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; C081226:FPCB protein, Sus scrofa; D014157:Transcription Factors; D004247:DNA; D000242:Cyclic AMP; D014568:Urokinase-Type Plasminogen Activator