Updated project metadata. By taking advantage of the strong genetic interactions between trans-translation and other ribosome rescue systems, we have employed a transposon sequencing (Tn-Seq) to identify potential novel rescue factors in Bacillus subtilis. In addition to the identification the ArfA-type rescue factor BrfA, as well as the RQC elongation actors RqcP and RqcH, our Tn-Seq screen led to the identification of YlmH, a poorly characterized S4-domain-containing protein, as a potential RQC factor. Binding of YlmH to 50S ribosomal subunit was confirmed by proteomics approach.