Characterization of the retinoid binding properties of the major fusion products present in acute promyelocytic leukemia cells

L Benedetti, A. A Levin, Bianca Maria Scicchitano, F Grignani, G Allenby, D Diverio, F Lo Coco, G Avvisati, M Ruthardt, S Adamo, P. G Pelicci, C. Nervi

Risultato della ricerca: Contributo in rivistaArticolo in rivista

34 Citazioni (Scopus)


The bcr1- and bcr3- promyelocytic leukemia/retinoic acid receptor alpha (PML/RAR alpha) are the two major fusion proteins expressed in acute promyelocytic leukemia (APL) patients. These proteins, which are present in different lengths of PML (amino acids 1-552 and 1-394, respectively), contain most of the functional domains of PML and RAR alpha, bind all-trans-retinoic acid (t-RA), and act as t-RA-dependent transcription factors. T-RA is an effective inducer of clinical remission only in patients carrying the t(15;17) and expressing the PML/RAR alpha products. However, in APL patients achieving complete remission with t-RA therapy the bcr3-PML/RAR alpha product has been found associated with a poorer prognosis than bcr1-PML/RAR alpha. In the present study we have investigated the structural and functional properties of the bcr3-PML/RAR alpha in comparison to the previously characterized bcr1-PML/RAR alpha. In particular, we have measured the binding properties of the two endogenous ligands t-RA and 9-cis-RA to both of these isoforms. T-RA binding analysis of nuclear and cytosolic extracts prepared from bcr3-PML/RAR alpha APL patients and from bcr3-PML/RAR alpha COS-1 transfected cells indicates that this protein is present only as high-molecular-weight nuclear complexes. Using saturation binding assays and Scatchard analyses we found that t-RA binds with slightly less affinity to the bcr3-PML/RAR alpha receptor than to bcr1-PML/RAR alpha or RAR alpha (Kd = 0.4 nmol/L, 0.13 nmol/L or 0.09 nmol/L, respectively). Moreover, two different high-affinity 9-cis-RA binding sites (Kd = 0.45 and 0.075 nmol/L) were detectable in the bcr3-PML/RAR alpha product but not in the bcr1-PML/RAR alpha product (Kd = 0.77 nmol/L). By competition binding experiments we showed that 9-cis-RA binds with higher specificity to the bcr3-PML/RAR alpha isoform than to the bcr1-PML/RAR alpha or RAR alpha. Consistent with these data, the binding of 9-cis-RA to the bcr3-PML/RAR alpha product resulted in increased transcriptional activation of the RA-responsive element (RARE) TRE, but not of the betaRARE, in transiently transfected COS-1 cells. These results provide evidence indicating that preferential retinoid binding to the different PML/RAR alpha products can be measured
Lingua originaleEnglish
pagine (da-a)1175-1185
Numero di pagine11
Stato di pubblicazionePubblicato - 1997


  • Animals
  • Antineoplastic Agents
  • Binding, Competitive
  • COS Cells
  • Chromosomes, Human, Pair 15
  • Chromosomes, Human, Pair 17
  • DNA-Binding Proteins
  • Gene Expression Regulation, Leukemic
  • Humans
  • Kruppel-Like Transcription Factors
  • Leukemia, Promyelocytic, Acute
  • Neoplasm Proteins
  • Oncogene Proteins, Fusion
  • Prognosis
  • Protein Binding
  • Recombinant Fusion Proteins
  • Remission Induction
  • Structure-Activity Relationship
  • Transcription Factors
  • Transcription, Genetic
  • Transfection
  • Translocation, Genetic
  • Tretinoin


Entra nei temi di ricerca di 'Characterization of the retinoid binding properties of the major fusion products present in acute promyelocytic leukemia cells'. Insieme formano una fingerprint unica.

Cita questo