hnRNP A1 may interact simultaneously with telomeric DNA and the human telomerase RNA in vitro.
The hnRNP A1 protein and a shortened derivative (UP1) promote telomere elongation in mammalian cells. In support of a direct role for A1 in telomere biogenesis, we have shown that the recombinant UP1 protein binds to telomeric DNA sequences in vitro, and pulls down telomerase activity from a cell extract. Here we show that A1/UP1 can interact directly with the RNA component of human telomerase (hTR). A portion of A1/UP1 that contains RNA recognition motif 2 (RRM2) is sufficient for an interaction with the first 208 nt of hTR. Given that the portion of A1/UP1 that contains RRM1 is sufficient for binding to a telomeric DNA oligonucleotide, we have tested whether A1/UP1 can interact simultaneously with both nucleic acids. Using a chromatography assay, we find that A1/UP1 bound to hTR can interact with telomeric DNA. Notably, these interactions are sufficiently robust to withstand incubation in a cell extract. Our results suggest that hnRNP A1 may help recruit telomerase to the ends of chromosomes.
Fiset
S
S
Département de Microbiologie et d'Infectiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada.
Chabot
B
B
D001665:Binding Sites; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000737:chemistry / Q000378:metabolism*; D019098:Telomerase / Q000235:genetics*; D016615:Telomere / Q000235:genetics*
D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012261:Ribonucleoproteins; C000619656:hnRNPA1 protein, human; D012313:RNA; D004247:DNA; D019098:Telomerase