Spleen focus-forming virus long terminal repeat insertional activation of the murine erythropoietin receptor gene in the T3Cl-2 friend leukemia cell line.
We have characterized the structure of the erythropoietin receptor gene promoter in normal murine erythroid tissues and in Friend-induced tumor cells. Using primer extension analysis, we identified two distinct transcriptional start sites, which were located 2 base pairs apart in anemic spleens, fetal liver, Friend-induced tumoral spleens, and mouse erythro-leukemia cells. In contrast, transcription was initiated 37 base pairs upstream of the normal cap sites in T3Cl-2, a Friend virus-induced murine erythroleukemia cell line. Also, the erythropoietin receptor mRNA in T3Cl-2 was overexpressed when compared with other erythroleukemia cell lines. We found that abnormal transcription occurring in T3Cl-2 cells resulted from an erythropoietin receptor gene alteration. Indeed, one erythropoietin receptor allele was rearranged by insertion of a spleen focus-forming virus long terminal repeat within the noncoding region of the first exon, 45 bases upstream of the ATG initiation codon and in the same 5'----3' orientation. The transcription of the rearranged allele was shown to be directed from the long terminal repeat promoter, leading to a long terminal repeat-erythropoietin receptor fusion transcript, whereas the normal erythropoietin receptor allele was weakly transcribed. Such altered receptor gene activation may provide a positive pressure in the development of tumorigenic erythroleukemia.
Lacombe
C
C
Institut Cochin de Génétique Moléculaire, Institut National de la Santé et de la Recherche Médicale (INSERM) U152, Paris, France.
Chrétien
S
S
Lemarchandel
V
V
Mayeux
P
P
Roméo
P H
PH
Gisselbrecht
S
S
Cartron
J P
JP
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004251:DNA Transposable Elements; D004921:Erythropoietin / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral; D005796:Genes; D007942:Leukemia, Experimental; D051379:Mice; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D015347:RNA Probes; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics*; D017467:Receptors, Erythropoietin; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D013155:Spleen Focus-Forming Viruses / Q000235:genetics*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D004251:DNA Transposable Elements; D015345:Oligonucleotide Probes; D015347:RNA Probes; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017467:Receptors, Erythropoietin; D004921:Erythropoietin; D004247:DNA