Nuclear interactions of retinoic acid-binding protein in chemically induced mammary adenocarcinoma.
Cellular retinoic acid-binding protein (CRABP) was detected in the nuclear fraction of N-methyl-N-nitrosourea-induced mammary cancers after the incubation of cytosol containing [3H]retinoic acid (RA)-bound CRABP with isolated nuclei. CRABP extracted from the nuclei in buffer containing 0.4 M-KCl sedimented as a 2 S component when subjected to sucrose-density-gradient analysis. [3H]RA-CRABP was found to be a prerequisite for the detection of nuclear binding, since the incubation of isolated nuclei or 0.4 M-KCl extract of the nuclei with [3H]RA did not result in any significant binding. Incubation of [3H]RA-CRABP at 25 or 30 degrees C before incubation with the nuclei neither altered the sedimentation coefficient nor enhanced the nuclear binding compared with 0 degrees C incubation. The tumour nuclei contained a saturable number of binding sites with a dissociation constant of 1.6 x 10(-9) M. These results indicate that the action of retinoic acid in the target organ may be mediated by its interaction with the nuclei.
D000230:Adenocarcinoma / Q000139:chemically induced / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D005260:Female; D066298:In Vitro Techniques; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000378:metabolism*; D008770:Methylnitrosourea; D009363:Neoplasm Proteins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D018168:Receptors, Retinoic Acid; D014212:Tretinoin / Q000378:metabolism
D002352:Carrier Proteins; D009363:Neoplasm Proteins; D018168:Receptors, Retinoic Acid; D014212:Tretinoin; D008770:Methylnitrosourea