Telomere biology and ribosome biogenesis: structural and functional interconnections

Telomeres are nucleoprotein structures that play a pivotal role in the protection and maintenance of eukaryotic chromo-somes. Telomeres and the enzyme telomerase, which replenishes telomeric DNA lost during replication, are important factors necessary to ensure continued cell proliferation. Cell proliferation is also dependent on proper and efficient protein synthesis, which is carried out by ribosomes. Mutations in genes involved in either ribosome biogenesis or telomere biology result in cellular abnormalities and can cause human genetic diseases, defined as ribosomopathies and telomeropathies, respectively. Interestingly, recent discoveries indicate that many of the ribosome assembly and rRNA maturation factors have additional noncanonical functions in telomere biology. Similarly, several key proteins and enzymes involved in telomere biology, in-cluding telomerase, have unexpected roles in rRNA transcription and maturation. These observations point to an intriguing cross-talk mechanism potentially explaining the multiple pleiotropic symptoms of mutations in many causal genes identified in various telomeropathy and ribosomopathy diseases. In this review, we provide a brief summary of eukaryotic telomere and rDNA loci structures, highlight several universal features of rRNA and telomerase biogenesis, evaluate intriguing interconnec-tions between telomere biology and ribosome assembly, and conclude with an assessment of overlapping features of human diseases of telomeropathies and ribosomopathies.

Automated summary

Telomeres are essential in protecting and maintaining eukaryotic chromosomes, and abnormalities in telomere biology can lead to genetic diseases. Recent discoveries have shown that factors involved in ribosome assembly and rRNA maturation also play roles in telomere biology, and key proteins and enzymes in telomere biology have unexpected functions in rRNA transcription and maturation. These findings suggest a potential cross-talk mechanism explaining the pleiotropic symptoms of telomeropathies and ribosomopathies.