A multimegabase cluster of snRNA and tRNA genes on chromosome 1p36 harbours an adenovirus/SV40 hybrid virus integration site.

Adenovirus type 12 (Ad12) induces gaps at chromosomal bands 1p36, 1q21, 1q42-43 and 17q21 after infection of human embryonic kidney cells. Three of these bands harbour small nuclear RNA genes or pseudogenes, but the study of a possible relationship has been hampered by the lytic character of adenovirus infection. A non-lytic Ad5/SV40 hybrid virus preferentially integrates at 1p36 and the integration site has been cloned. Chromosomal band 1p36 encodes genes for small nuclear RNA U1 (RNU-1) and for the tRNAs of glutamic acid (TRE) and asparagine (TRN). Each of these genes is encoded by 15-30 copies. We studied the organization of these genes and of the viral integration site by pulsed field gel electrophoresis (PFGE) and analysis of yeast artificial chromosomes (YACs). We show that RNU-1, TRE and TRN genes are scattered over a region of probably more than 2 Mb with intergenic distances of up to 125 kb. The Ad5/SV40 integration site maps to identical chromosomal NotI fragments as RNU-1 and TRE. Fine mapping of a YAC shows that the integration site is within 40-70 kb of genes for RNU-1, TRN and TRE.