The disclosure provides nucleotide analogs and methods of their use. Analogs of the invention comprise a reporter molecule (label) attached via the N4, N6, O4, or O6 position of the nitrogenous base portion of the analog. In a preferred embodiment, nucleotide analogs of the invention comprise a label attached to the nitrogenous base portion of the analog via a cleavable linker at the N4, O4, N6 or O6 position.