Coilin is widely known as the protein marker of the Cajal body, a subnuclear 
domain important to the biogenesis of small nuclear ribonucleoproteins and 
telomerase, complexes that are crucial to pre-messenger RNA splicing and 
telomere maintenance, respectively. Extensive studies have characterized the 
interaction between coilin and the various other protein components of CBs and 
related subnuclear domains; however, only a few have examined interactions 
between coilin and nucleic acid. We have recently published that coilin is 
tightly associated with nucleic acid, displays RNase activity in vitro, and is 
redistributed to the ribosomal RNA (rRNA)-rich nucleoli in cells treated with 
the DNA-damaging agents cisplatin and etoposide. Here, we report a specific in 
vivo association between coilin and rRNA, U small nuclear RNA (snRNA), and human 
telomerase RNA, which is altered upon treatment with DNA-damaging agents. Using 
chromatin immunoprecipitation, we provide evidence of coilin interaction with 
specific regions of U snRNA gene loci. We have also utilized bacterially 
expressed coilin fragments in order to map the region(s) important for RNA 
binding and RNase activity in vitro. Additionally, we provide evidence of coilin 
involvement in the processing of human telomerase RNA both in vitro and in vivo.