Genome-wide annotation of small RNAs expressed in HeLa and HepG2 cells

We report an applicaton of small RNA sequencing using high throughput next generation sequencing to identify the small RNA content of cell lines. By sequencing over 30 million reads we could identify a new class of small RNAs previousy observed with tiling arrays and mapping to promoter regions of coding genes. We also identified a large number of small RNAs corresponding to internal exons of coding genes. By using different enzymatic treatments and immunoprecipitation experiments, we have determined that both the promoter associated small RNAs as well as ones within the body of the genes bear 5' cap structures. Examination of the expression of small RNAs (<200nt).