This an editor's note regarding: Igor Shevelev, Giuseppina Blanca, Giuseppe Villani, Kristijan Ramadan, Silvio Spadari, Ulrich Hübscher, Giovanni Maga, Mutagenesis of human DNA polymerase λ: essential roles of Tyr505 and Phe506 for both DNA polymerase and terminal transferase activities, Nucleic Acids Research, Volume 31, Issue 23, 1 December 2003, Pages 6916–6925, https://doi.org/10.1093/nar/gkg896
In February 2025, the Editors were made aware of potential vertical splice lines between lanes 3 and 4, lanes 6 and 7, and after lane 12 in Figure 1A, and between lanes 4 and 5 in Figure 1B. There may also be a horizontal splice line in lanes 4-6 above the lowest two bands in Figure 1A. These concerns have also been raised on PubPeer (https://pubpeer.com/publications/75490A890A40717419697D0667D67F).
The article was published in 2003. Both the first and corresponding authors have since passed away, and the lab where most of the work was done closed 10 years ago. Hence, the remaining authors no longer have the original data. They have provided the following explanation:
“It is quite evident that Figure 1A was assembled from multiple gels. Specifically, the F506G and F506R variants were analysed on two separate gels, while Y505A and WT were run on the same gel. In addition, a radioactive control reaction without the enzyme was run on a fourth gel. Importantly, each DNA pol λ variant (DNA pol λ F506G, F506R, Y505A, and WT) was run at varying concentrations on the same gel. Since this is a DNA sequencing gel, each extended nucleotide on the radioactively labelled primer is distinctly visible, making it clear that increased concentrations of DNA polymerase λ variants enhance DNA primer extension. Furthermore, both F506G and F506R exhibit a marked defect in activity compared to the wild type or Y505A.
For Figure 1B, we cannot comment without the original gel/data. However, it is clear that Figure 1B was also assembled from 4 different gels (each gel for one variant of the DNA pol λ enzyme), but most importantly, each variant was analysed on the same gel”.
The Editors believe that the apparent horizontal splice line in Figure 1A is a jpeg compression artefact. However, in the absence of original data, the Editors advise readers to examine Figures 1A and B with care.
Julian E. Sale and Barry L. Stoddard
Senior Executive Editors