PML/RARalpha fusion protein transactivates the tissue factor promoter through a GAGC-containing element without direct DNA association.
A severe coagulopathy is a life-threatening complication of acute promyelocytic leukemia (APL) and is ascribable mainly to the excessive levels of tissue factor (TF) in APL cells regulated in response to the promyelocytic leukemia/retinoic acid receptor alpha (PML/RARalpha) fusion protein. The underlying molecular mechanisms for this regulation remain ill-defined. With U937-PR9 cell lines stably expressing luciferase reporter gene under the control of different mutants of the TF promoter, both luciferase and ChIP data allowed the localization of the PML/RARalpha-responsive sequence in a previously undefined region of the TF promoter at position -230 to -242 devoid of known mammalian transcription factor binding sites. Within this sequence a GAGC motif (-235 to -238) was shown to be crucial because deletion or mutation of these nucleotides impaired both PML/RARalpha interaction and promoter transactivation. However, EMSA results showed that PML/RARalpha did not bind to DNA probes encompassing the -230 to -242 sequences, precluding a direct DNA association. Mutational experiments further suggest that the activator protein 1 (AP-1) sites of the TF promoter are dispensable for PML/RARalpha regulation. This study shows that PML/RARalpha transactivates the TF promoter through an indirect interaction with an element composed of a GAGC motif and the flanking nucleotides, independent of AP-1 binding.
Yan
Jinsong
J
Shanghai Institute of Hematology, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
Wang
Kankan
K
Dong
Leiming
L
Liu
Hongchen
H
Chen
Weiqin
W
Xi
Wenda
W
Ding
Qiulan
Q
Kieffer
Nelly
N
Caen
Jacques P
JP
Chen
Saijuan
S
Chen
Zhu
Z
Xi
Xiaodong
X
D001483:Base Sequence; D045744:Cell Line, Tumor; D020147:Coagulation Protein Disorders / Q000209:etiology / Q000235:genetics*; D004247:DNA / Q000378:metabolism; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000150:complications*; D015514:Oncogene Proteins, Fusion / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D013925:Thromboplastin / Q000235:genetics*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D015533:Transcriptional Activation
D015514:Oncogene Proteins, Fusion; D018808:Transcription Factor AP-1; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein; D004247:DNA; D013925:Thromboplastin