title: The impact of multiple splice sites in human L1 elements.
abstract: LINE-1 elements represent a significant proportion of mammalian genomes. The impact of their activity on the structure and function of the host genomes has been recognized from the time of their discovery as an endogenous source of insertional mutagenesis. L1 elements contain numerous functional internal polyadenylation signals and splice sites that generate a variety of processed L1 transcripts. These sites are also reported to contribute to the generation of hybrid transcripts between L1 elements and host genes. Using northern blot analysis we demonstrate that L1 splicing, but not L1 polyadenylation, is delayed during the course of L1 expression. L1 splicing can also be negatively regulated by EBV SM protein known to alter this process. These results suggest a potential for L1 mRNA processing to be regulated in a tissue- and/or development-specific manner. The delay in L1 splicing may also serve to protect host genes from the excessive burden of L1 interference with their normal expression via aberrant splicing.
authors.affiliation: Tulane Cancer Center, SL66, Department of Epidemiology, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans, LA 70112, USA.
authors.forename: V P
authors.initials: VP
authors.lastname: Belancio
authors.forename: A M
authors.initials: AM
authors.lastname: Roy-Engel
authors.forename: P
authors.initials: P
authors.lastname: Deininger
mesh_terms: D020121:5' Untranslated Regions; D000818:Animals; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D017874:Immediate-Early Proteins / Q000494:pharmacology; D007438:Introns; D020084:Long Interspersed Nucleotide Elements / Q000502:physiology*; D051379:Mice; D008957:Models, Genetic; D041681:NIH 3T3 Cells; D026723:Polyadenylation; D022821:RNA Splice Sites; D012326:RNA Splicing; D015534:Trans-Activators / Q000494:pharmacology; D014764:Viral Proteins / Q000494:pharmacology
chemical_list: D020121:5' Untranslated Regions; C068382:BRLF1 protein, Human herpesvirus 4; D017874:Immediate-Early Proteins; D022821:RNA Splice Sites; D015534:Trans-Activators; D014764:Viral Proteins