IP Staufen2

In human cells, Staufen2 is a double-stranded RNA-binding protein involved in several cellular functions. Although 51% identical to Staufen1, these proteins are nevertheless found in different RNA particles. In addition, differential splicing events generate Staufen2 isoforms that only differ at their N-terminal extremities. We used a genome wide approach to identify and compare the mRNA targets of mammalian Staufen2 isoforms. The mRNA content of Staufen mRNPs was identified by probing DNA microarrays with probes derived from mRNAs isolated from immunopurified Staufen2-containing complexes following transfection of HEK293T cells with Stau2-HA (59kDa) or Stau2-HA (62kDa) expressors. Our results indicate that 11% of the cellular RNAs expressed in HEK293T cells are found in Stau2-containing mRNPs. There is a predominance of mRNAs involved in cell metabolism, transport, transcription, regulation of cell processes and catalytic activity. Keywords: Immunoprecipitation, Staufen, microarray HEK293 cells were transiantly transfected with plasmids coding for Staufen2-HA isoforms. Cell extracts were immunoprecipitated using anti-HA antibodies and co-immunoprecipitated mRNAs were purified and used to hybridize microarrays. As control, cell extract from mock transfected cells were used.