A dominant negative mutation of the alpha retinoic acid receptor gene in a retinoic acid-nonresponsive embryonal carcinoma cell.

Abstract

Pluripotential embryonal carcinoma cells such as those of the P19 line differentiate when exposed to retinoic acid (RA). The RAC65 cell line is a mutant clone of P19 cells selected to be RA nonresponsive. RAC65 cells carry a rearrangement affecting one of the genes encoding a nuclear retinoic acid receptor (RAR alpha). The mutant gene encodes a protein, RAR alpha', that has lost its 70 C-terminal amino acids, thus truncating the RA-binding domain. The RAR alpha' was found to be a dominant repressor of transcription from an RA-responsive target gene; however, expression of RAR alpha' was insufficient to confer RA nonresponsiveness, suggesting that RAC65 cells carry an additional mutation(s) affecting RA-induced genes.

Functional specificity of the two retinoic acid receptor RAR and RXR families in myogenesis

“…Examples include a translocation breakpoint in RARa at the genetic lesion of acute promyelocytic leukemia ( The data from panel a were quanti®ed by densitometry and expressed relative to S26 mRNA levels which serve as control of RNA loading. This experiment was performed twice dominant negative RARa mutants in retinoid-resistant embryonic carcinoma lines (Pratt et al, 1990;Kruyt et al, 1992), in RA-resistant HL-60 cells (Collins et al, 1990;Robertson et al, 1992), expression of dominant negative RXRb mutant in P19 embryonal carcinoma cells (Minucci et al, 1994), absence of RXRa expression in RA-resistant myogenic C2 cells (Froeschle et al, 1996) and F9 embryonal carcinoma cells bearing single and compound RAR and RXR mutations (Boylan et al, 1993(Boylan et al, , 1995Cli ord et al, 1996;Chiba et al, 1997). Interestingly, in all these cases, proliferation characteristics and/or retinoidinduced di erentiation are altered.…”

RAR-mediated epigenetic control of the cytochrome P450 Cyp26a1 in embryocarcinoma cells

“…In contrast, its mutant counterpart, the RAC65 cell line, is RA-resistant and cannot differentiate when grown as aggregates (Jones-Villeneuve et al, 1983). RAC65 harbors a mutant RARa protein, originally designated RARa 0 (Pratt et al, 1990). The wild-type RARa has six distinct protein domains, A-F, including the C domain, capable of binding the RARE of target genes, and the E domain harboring the RA-binding domain (Laudet and Gronemeyer, 2002 and references within).…”

“…The mutant RARa 0 lacks part of the E-domain ( Figure 1a) as a consequence of a genetic insertion in the wild type RARa, but retains the C domain. The biological features of RAC65 are mostly due to the defective RARa 0 , which exerts a dominant negative action on the wild type RARa (Pratt et al, 1990;Kruyt et al, 1992). RARa 0 prevents the transactivation of RA-responsive genes resulting in a block of neuron differentiation in response to RA (Kruyt et al, 1992;Costa and McBurney, 1996).…”

A mutated PML/RARA found in the retinoid maturation resistant NB4 subclone, NB4-R2, blocks RARA and wild-type PML/RARA transcriptional activities

“…28 Moreover, these mutations are localized near other codons; codon 391 or codons 406, 407 and 410 reportedly important for RARA function. 29,30 We describe here a new mutation in codon 903 (codon 411 in the RARA nomenclature) in the E-domain of the RAR moiety of PML/RARA leading to the deletion of the C-terminal 52 amino acids. The region deleted by this mutation comprises four of the seven residues constituting the ␣-helix 12 which includes the AF2 part of the E-domain.…”