Genomic Organization of IgH Gene Compared With the Expression of Bcl-2 Gene in t(14;18)-Positive Lymphoma

• Published in: Blood Vol. 77; no. 9; pp. 1970 - 1976
• Main Authors: Amakawa, Ryuichi, Fukuhara, Shirou, Ohno, Hitoshi, Matsuyama, Fumino, Kato, Isoroku, Tanabe, Satoru, Sideras, Pascalis, Mizuta, Tatsunobu-Ryushin, Honjo, Tasuku, Okuma, Minoru
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 01-05-1991; The Americain Society of Hematology
• Subjects: Biological and medical sciences; Deoxyribonuclease BamHI; Deoxyribonuclease EcoRI; Deoxyribonuclease HindIII; Deoxyribonucleases, Type II Site-Specific; DNA Probes; Gene Expression; Hematologic and hematopoietic diseases; Immunoglobulin Heavy Chains - genetics; Karyotyping; Lymphoma - genetics; Medical sciences; Nucleic Acid Hybridization; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins c-bcl-2; RNA, Messenger - metabolism; Transcription, Genetic; Tumor Cells, Cultured; Human; Exploration; Genome organization; Malignant hemopathy; Experimental study; Lymphoproliferative syndrome
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V77.9.1970.1970

In three lymphoma cell lines carrying t(14;18), named FL-18, FL-218, and FL-318, the genomic organization of IgH gene was compared with the expression of bcl-2 gene; the t(14;18) of the FL-18 cells occurred downstream from the major breakpoint cluster region (mbr) of a bcl-2 gene, and that of the FL-218 and FL-318 cells within the mbr. The FL-318 expressed the normal-sized bcl-2 transcript of 8.5-kb mRNA having the noncoding region 3' to the mbr, which was found in the FL-18, and the FL-218 lacking the intact bcl-2 gene did not. This finding suggests that in t(14;18)-positive lymphoma having the breakpoint within the mbr, transcription of the nontranslocated bcl-2 allele is not necessarily silent. In addition, the FL-218 and FL-318 expressed aberrant bcl-2 transcripts and heterogenous IgH transcripts lacking the VH region, and the bcl-2 transcripts each comigrated with parts of the sterile IgH mRIMAs. The FL-318, which did not exhibit switch recombination on either IgH allele, contained abundant amounts of Iγ mRNAs, a prerequisite for the recombination into the Cγ locus. One of the I-mRNA species comigrated with the aberrant bcl-2 transcript. The FL-18 and FL-218 lacking the Iγ mRNAs had completed switch recombination of both IgH alleles. This result raises a possibility that deregulated bcl-2 transcription caused by t(14;18) is capable of playing a role in class switch recombination of IgH gene.