BackgroundAlzheimer's disease (AD) is a progressive neurodegenerative characterized by amyloid-β (Aβ) peptide aggregation and tangles. Protein translation deregulation and viral exposures, including S Show more
BackgroundAlzheimer's disease (AD) is a progressive neurodegenerative characterized by amyloid-β (Aβ) peptide aggregation and tangles. Protein translation deregulation and viral exposures, including SARS-CoV-2, have been implicated in increased AD risk. Genes such as YIF1A, PABPC4, and MRPS27, which are involved in mRNA translation and protein folding have been linked to neurodegeneration and host responses to SARS-CoV-2.ObjectiveThis study investigates the association of three genetic variants, rs7945723G>A Show less
Tight regulation of developmental pathways is of critical importance to all organisms, and is achieved by a transcriptional cascade ensuring the coordinated expression of sets of genes. We aimed to ex Show more
Tight regulation of developmental pathways is of critical importance to all organisms, and is achieved by a transcriptional cascade ensuring the coordinated expression of sets of genes. We aimed to explore whether a strong signal is required to enter and complete a developmental pathway, by using meiosis in budding yeast as a model. We demonstrate that meiosis in budding yeast is insensitive to drastic changes in the levels of its consecutive positive regulators (Ime1, Ime2, and Ndt80). Entry into DNA replication is not correlated with the time of transcription of the early genes that regulate this event. Entry into nuclear division is directly regulated by the time of transcription of the middle genes, as premature transcription of their activator NDT80, leads to a premature entry into the first meiotic division, and loss of coordination between DNA replication and nuclear division. We demonstrate that Cdk1/Cln3 functions as a negative regulator of Ime2, and that ectopic expression of Cln3 delays entry into nuclear division as well as NDT80 transcription. Because Ime2 functions as a positive regulator for premeiotic DNA replication and NDT80 transcription, as well as a negative regulator of Cdk/Cln, we suggest that a double negative feedback loop between Ime2 and Cdk1/Cln3 promotes a bistable switch from the cell cycle to meiosis. Moreover, our results suggest a regulatory mode switch that ensures robust meiosis as the transcription of the early meiosis-specific genes responds in a graded mode to Ime1 levels, whereas that of the middle and late genes as well as initiation of DNA replication, are regulated in a threshold mode. Show less