Abstract The Juvenile form of Batten disease is a neurodegenerative disease with symptoms starting in the first decade and ending in death in the third decade of life. The gene defective in this form of Batten disease, CLN3 , is conserved in eukaryotes, suggesting that the gene product serves a basic function in the cell, though the function is unknown. We have investigated the expression and regulation of the yeast homolog BTN1. Reanalysis of publicly available gene expression data suggests that transcription of BTN1 increases in response to oxidative stress, treatment with rapamycin or arsenate, amino acid starvation, and sporulation conditions. Similar to GCN4, there are upstream open reading frames (uORF) in front of BTN1, suggesting translational regulation. We developed reporter strains in which the HIS3 open reading frame replaced that of the BTN1 gene, with and without the uORFs. These reporters show that one or more of the uORFs decrease the expression of the HIS3 reporter. When expressed in the reporter strain using a high copy vector, GCN3, tRNA Arg , and tRNA Leu , increase expression, suggesting the involvement of the TORC1 pathway. BIT61 abuts BTN1 but is encoded on the opposite strand; 3’ RACE analysis indicates that the mRNA of BIT61 overlaps with that of BTN1. BIT61 is involved in the TORC2 pathway, which interacts with the TORC1 pathway, suggesting a possible cis-acting mechanism of co-regulation. Lastly, we demonstrate that a yeast strain with a null mutation in BTN1 is sensitive to selective amino acid starvation, further supporting the association of BTN1 with TORC1.
Pillalamarri et al. (Wed,) studied this question.