Analysis of c-erb A RNA expression in the triiodothyronine-sensitive Ob 17 preadipocyte cell line.
The protooncogenes erb A alpha and beta encode, in the rat, three functional thyroid hormone receptors (erb A alpha 1, beta 1 and beta 2), and two isoforms (erb A alpha 2, alpha 3) that do not bind triiodothyronine (T3). We previously reported on a mouse preadipocyte cell line (Ob 17) which was found to be sensitive to thyroid hormones and retinoic acid. Using antibodies or cDNA probes, we reported that the c-erb A products are mainly of the alpha-type in these cells. We also showed that the thyroid hormone receptors/c-erb A products are down-regulated moderately by T3 and strongly by retinoic acid added to the culture medium. In this work, different c-erb A subtypes are identified in this mouse cell line. Using couples of oligonucleotides known to be specific of each rat c-erb A subtype, we could detect the presence of alpha 1, alpha 2 and beta 1-type transcripts. We also detected Rev transcripts of a Reverse erb A alpha gene present in the rat at the c-erb A alpha locus and that contains a region complementary to the c-erb A alpha 2-specific region. These transcripts were identified by PCR amplification from cell cDNAs and in Northern analyses using the corresponding PCR-designed c-erb A probes. All the detected transcripts were found to be down-regulated by retinoic acid.
INSERM U38, Biochimie Médicale, Faculté de Médecine, Marseille, France.
M
M
Teboul
J
J
Torresani
D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D015870:Gene Expression; D051379:Mice; D008820:Mice, Obese; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D011988:Receptors, Thyroid Hormone / Q000235:genetics; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism*; D014284:Triiodothyronine / Q000494:pharmacology*
D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011988:Receptors, Thyroid Hormone; D014284:Triiodothyronine