Genomic structure of the human retinoblastoma-related Rb2/p130 gene.

The human Rb2/p130 gene shares many structural and functional features with the retinoblastoma gene and the retinoblastoma-related p107 gene. In the present study, we have cloned and partially sequenced the gene coding for the Rb2/p130 protein from human genomic libraries. The complete intron-exon organization of this gene has been elucidated. The gene contains 22 exons spanning over 50 kb of genomic DNA. The length of individual exons ranges from 65 to 1517 bp. The largest intron spans over 9 kb, and the smallest has only 82 bp. The 5' flanking region revealed a structural organization characteristic of promoters of "housekeeping" and growth control-related genes. A typical TATA or CAAT box is not present, but there are several GC boxes and potential binding sites for numerous transcription factors. This study provides the molecular basis for understanding the transcriptional control of the Rb2/p130 gene and for implementing a comprehensive Rb2/p130 mutation screen using genomic DNA as a template.