Biology subjects

Thoreen, C. C.

Publications and source records attributed to Thoreen, C. C..

3 recordsLinked to original sources

bioRxiv2025

Larp1 supports brain growth and spatial memory via post-transcriptional control of the translation machinery

In the brain, tight regulation of the translation of mRNAs is essential for development and plasticity. The translation machinery itself is largely encoded by mRNAs with terminal oligopyrimidine (TOP) motifs, which can be post-transcriptionally controlled by the mTOR signaling pathway. In neurons, these mRNAs are selectively enriched in axons, dendrites and synapses, suggesting local functions for their regulation. Here, we use a brain-specific knockout of the mTOR effector and TOP mRNA binding protein, Larp1, to uncover its role in brain development and behavior. Loss of Larp1 significantly decreases brain mass and reduces the density of neurons. We find that TOP mRNAs levels are depleted by more than 50% and selectively lost from synapses, reversing the enrichment that occurs when Larp1 is present. In behavior tests, Larp1-deficient mice are severely impaired in spatial learning and memory. These results demonstrate a critical role for Larp1 in maintaining the levels of essential mRNAs necessary for brain growth and highlight the importance of post-transcriptional regulation by mTOR for normal learning and memory.

neuroscience↗

bioRxiv2024

Quantitative profiling of human translation initiation reveals regulatory elements that potently affect endogenous and therapeutically modified mRNAs

mRNA therapeutics offer a potentially universal strategy for the efficient development and delivery of therapeutic proteins. Current mRNA vaccines include chemically modified nucleotides to reduce cellular immunogenicity. Here, we develop an efficient, high-throughput method to measure human translation initiation on therapeutically modified as well as endogenous RNAs. Using systems-level biochemistry, we quantify ribosome recruitment to tens of thousands of human 5' untranslated regions and identify sequences that mediate 250-fold effects. We observe widespread effects of coding sequences on translation initiation and identify small regulatory elements of 3-6 nucleotides that are sufficient to potently affect translational output. Incorporation of N1-methylpseudouridine (m1{Psi}) selectively enhances translation by specific 5' UTRs that we demonstrate surpass those of current mRNA vaccines. Our approach is broadly applicable to dissect mechanisms of human translation initiation and engineer more potent therapeutic mRNAs. HighlightsO_LIMeasurement of >30,000 human 5' UTRs reveals a 250-fold range of translation output C_LIO_LISystematic mutagenesis demonstrates the causality of short (3-6nt) regulatory elements C_LIO_LIN1-methylpseudouridine alters translation initiation in a sequence-specific manner C_LIO_LIOptimal modified 5' UTRs outperform those in the current class of mRNA vaccines C_LI

systems biology↗

bioRxiv2019

Archaeal ribosomal proteins possess nuclear localization signal-type motifs: implications for the origin of the cell nucleus

AO_SCPLOWBSTRACTC_SCPLOWEukaryotic cells are divided into the nucleus and the cytosol, and, to enter the nucleus, proteins typically possess short signal sequences, known as nuclear localization signals (NLSs). Although NLSs have long been considered as features unique to eukaryotic proteins, we show here that similar or identical protein segments are present in ribosomal proteins from the Archaea. Specifically, the ribosomal proteins uL3, uL15, uL18, and uS12 possess NLS-type motifs that are conserved across all major branches of the Archaea, including the most ancient groups Microarchaeota and Diapherotrites, pointing to the ancient origin of NLS-type motifs in the Archaea. Furthermore, by using fluorescence microscopy, we show that the archaeal NLS-type motifs can functionally substitute eukaryotic NLSs and direct the transport of ribosomal proteins into the nuclei of human cells. Collectively, these findings illustrate that the origin of NLSs preceded the origin of the cell nucleus, suggesting that the initial function of NLSs was not related to intracellular trafficking. Overall, our study reveals rare evolutionary intermediates among archaeal cells that can help elucidate the sequence of events that led to the origin of the eukaryotic cell.

evolutionary biology↗