TRNT1 Mutations in SIFD: Investigating the Genetics of a Rare Childhood Disease Through Yeast

Mitochondrial diseases span a wide spectrum of disorders, varying in severity and symptoms. These diseases are often caused by mutations in either the nuclear or mitochondrial genome. Frequently, mutations occur in genes which impact the maturation of tRNA (Karasik et al., 2021). A key player in this process is the CCA-adding enzyme, responsible for modifying both nuclear and mitochondrial tRNAs. This enzyme is encoded by the nuclear gene TRNT1, and partial loss-of-function mutations in TRNT1 cause several diseases, most prominently SIFD (sideroblastic anemia with B-Cell immunodeficiency, periodic fevers, and developmental delay; Pranesh et al., 2014). Although it is known that TRNT1 mutations cause SIFD, there is a lack of knowledge on how various TRNT1 mutations are associated with the wide range of phenotypes presented in SIFD patients. Yeast can be used as a valuable model organism for investigating the specific TRNT1 mutations associated with SIFD due to the presence of a conserved TRNT1 homologue, Cca1 (Slade, et al., 2020). Throughout this project, plasmids carrying various patient-associated TRNT1 mutations were introduced into a yeast strain in which the endogenous Cca1 could be depleted using a plant hormone auxin, and subsequently tested for their ability to rescue yeast growth. This study outlines the experimental approach used to analyze the patient-associated TRNT1 mutations, identifies potential detrimental TRNT1 mutations at positions 295, 316, 461, 745, 947, and 1234, and underscores the importance of further research on SIFD associated mutations.