Understanding the intricacies of telomerase regulation is crucial due to the potential health benefits of modifying its activity. Telomerase is composed of an RNA component and reverse transcriptase. However, additional factors required during biogenesis vary between species. Here we have identified fission yeast Lar7 as a member of the conserved LARP7 family, which includes the Tetrahymena telomerase-binding protein p65 and human LARP7. We show that Lar7 has conserved RNA-recognition motifs, which bind telomerase RNA to protect it from exosomal degradation. In addition, Lar7 is required to stabilise the association of telomerase RNA with the protective complex LSm2–8, and telomerase reverse transcriptase. Lar7 remains a component of the mature telomerase complex and is required for telomerase localisation to the telomere. Collectively, we demonstrate that Lar7 is a crucial player in fission yeast telomerase biogenesis, similarly to p65 in Tetrahymena, and highlight the LARP7 family as a conserved factor in telomere maintenance.

Background: Based on an initial collecting of database sequences from the gap junction protein gene family (also called connexin genes) in a few teleosts, the naming of these sequences appeared variable. The reasons could be (i) that the structure in this family is variable across teleosts, or (ii) unfortunate naming. Rather clear rules for the naming of genes in fish and mammals have been outlined by nomenclature committees, including the naming of orthologous and ohnologous genes. We therefore analyzed the connexin gene family in teleosts in more detail. We covered the range of divergence times in teleosts (eel, Atlantic herring, zebrafish, Atlantic cod, three-spined stickleback, Japanese pufferfish and spotted pufferfish; listed from early divergence to late divergence). Results: The gene family pattern of connexin genes is similar across the analyzed teleosts. However, (i) several nomenclature systems are used, (ii) specific orthologous groups contain genes that are named differently in different species, (iii) several distinct genes have the same name in a species, and (iv) some genes have incorrect names. The latter includes a human connexin pseudogene, claimed as GJA4P, but which in reality is Cx39.2P (a delta subfamily gene often called GJD2like). We point out the ohnologous pairs of genes in teleosts, and we suggest a more consistent nomenclature following the outlined rules from the nomenclature committees. We further show that connexin sequences can indicate some errors in two high-quality chromosome assemblies that became available very recently. Conclusions: Minimal consistency exists in the present practice of naming teleost connexin genes. A consistent and unified nomenclature would be an advantage for future automatic annotations and would make various types of subsequent genetic analyses easier. Additionally, roughly 5% of the connexin sequences point out misassemblies in the new high-quality chromosome assemblies from herring and cod.

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