Genomic Organization, Promoter Region Analysis, and Chromosome Localization of the Mouse bcl-x Gene

Didier A M Grillot, Maribel González-García, Daryoush Ekhterae, Linda Duan, Naohiro Inohara, Shigeo Ohta, Michael F Seldin, Gabriel Núñez

Research output: Contribution to journalArticlepeer-review

178 Scopus citations


The bcl-x gene, a bcl-2 family member, is highly regulated during lymphoid development, and its expression modulates apoptosis in lymphoid and other cell populations. Several forms of bcl-x mRNAs with different biologic functions have been described in rodents and humans. In this study, we have determined the organization and promoter region of the mouse bcl-x gene in an effort to understand the molecular basis for the different bcl-x mRNA species identified in tissues. We show that mouse bcl-x maps to the distal mouse chromosome 2 at approximately 89 cM, and exhibits a three-exon structure with an untranslated first exon and a facultative first intron. The coding region of bcl-xL is generated by the juncture of exons II and III through a splicing reaction, whereas bcl-xS is generated by an alternatively utilized donor splice site located within exon II. Analysis of multiple cDNAs and primer extension experiments revealed major transcription initiation sites in brain and thymus within a GC-rich region, with multiple Sp1-binding motifs located upstream of exon I. Another promoter was mapped to a 57-bp region localized upstream of the translation initiation codon by transfection of reporter constructs into FL5.12 and K562 cell lines. The remarkable similarity between the genomic regions of bcl-2 and bcl-x suggests that these genes have evolved from a common ancestral gene or through gene duplication.

Original languageEnglish (US)
Pages (from-to)4750-4757
Number of pages8
JournalJournal of Immunology
Issue number10
StatePublished - May 15 1997

ASJC Scopus subject areas

  • Immunology


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