NCL1 transcript levels were measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in HEK293T cells at 24 hours. We compared NCL1 transcript levels upon NCL1 2'-OMe LyTON treatment to the unconjugated NCL1 2'-OMe ASO, all normalised to the housekeeping gene GAPDH. As expected, the NCL1 2'-OMe ASO showed poor knockdown, as it is only able to sterically block the target mRNA. The NCL1 2'-OMe LyTON far outperformed its unconjugated counterpart at all concentrations tested (Figure ). We measured 46.9%, 59.1%, 55.0%, less transcript upon treatment with the NCL1 2'-OMe LyTON conjugate, compared to the unconjugated NCL1 2'-OMe ASO, at 50, 100, and 200 nM respectively. This NCL1 ASO sequence was originally designed for RNase H-mediated knockdown as a 'gapmer'. The current state-of-the-art for ASO modification chemistry is the 'gapmer' design comprised of wings of five bases containing 2'-methoxyethyl sugars and a central DNA region (Figure ). Thus, we also sought to compare the activity of the NCL1 2'-OMe LyTON to the previously validated NCL1 'gapmer' ASO. As expected, at 100 nM, the NCL1 gapmer performed better than the RNase H-inactive NCL1 2'-OMe version (Figure ). However, the NCL1 2'-OMe LyTON performed significantly better than even the NCL1 gapmer, with 34.9% less transcript observed (Figure , SI Figure ). This indicated that degrading mRNA via a lysosomal pathway might be more efficient for gene knockdown than relying upon RNase H recruitment, primarily, in the nucleus.