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This study characterizes the role of ribosomal protein eL22 in the assembly of the large 60S ribosomal subunit in the yeast Saccharomyces cerevisiae. The researchers demonstrate that eL22 incorporates into intermediate nucleolar pre-60S particles, and its absence impairs cell growth, reduces 60S subunit accumulation, and disrupts the maturation of 27SB pre-ribosomal RNA, with these defects being more pronounced at low temperatures. Additionally, genetic interactions were identified between eL22 and neighboring ribosomal proteins eL38 and eL31, suggesting cooperative roles among proteins associated with common structural elements of the 25S ribosomal RNA.
Why it matters
Human eL22 has been implicated in p53 regulation during ribosomal stress and is frequently mutated in certain cancers, making a clearer understanding of its function in ribosome biogenesis relevant to the study of cancer biology and ribosomal stress-related diseases. This work provides a mechanistic foundation that may help clarify how eL22 dysfunction contributes to pathological conditions in humans.
⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Ribosome biogenesis is a highly coordinated pathway that involves the assembly of ribosomal RNAs (rRNAs) with ribosomal proteins (r-proteins) to generate functional ribosomal subunits (r-subunits). The Saccharomyces cerevisiae (yeast) large 60S r-subunit consists of three rRNA molecules and 46 r- proteins. The contributions of nearly all r-proteins of the yeast large r-subunit have been characterized; however, a few non-essential proteins remain poorly understood. Although non-essential, human eL22 has been identified as a key player in p53 regulation during ribosomal stress and as a highly mutated target in cancers. Despite this function, the role of eL22 in ribosome maturation is still ill-defined. In this study, we characterized yeast eL22 r-protein. Our results show that eL22 assembles into intermediate nucleolar pre-60S ribosomal particles. Loss of eL22 impairs cell growth and reduces 60S r-subunit accumulation, phenotypes that are exacerbated at low temperatures. Analysis of pre-rRNA processing by pulse-chase labeling, northern blot hybridization, and primer extension reveals a defect in 27S pre- rRNA maturation, specifically at the level of 27SB pre-rRNA processing. Consequently, nuclear export of eL22-deficient pre-60S particles is mildly impaired. Furthermore, we identify genetic interactions between eL22 and neighboring r-proteins, eL38 and eL31. We conclude that eL22 assembly is required for optimal pre-60S maturation during middle nucleolar stages, particularly at low temperatures, a function likely supported by the cooperative action of other r-proteins associated with common elements of 25S rRNA.