Akira Katayama

Amyotrophic lateral sclerosis/frontotemporal lobar degeneration‐linked proteins, TDP‐43 and fused in sarcoma (FUS), bind to G‐quadruplex‐containing mRNAs and transport them to distal neurites for local translation. The specificity and mechanism of G4‐RNA binding, however, remain largely unsolved. Using purified full‐length TDP‐43 and FUS and a set of seven G4‐DNA/RNA, we compared their recognition properties of G4‐RNAs. Both TDP‐43 and FUS recognized and bound to G4‐DNA/RNAs, but the target selectivity differed between two proteins. TDP‐43 recognized only parallel‐stranded G4‐DNA/RNAs, leading to stabilize the G4 conformation. In contrast, FUS bound to all three types, parallel, hybrid, and antiparallel, of G4‐DNA/RNAs, resulting in deformation of the G4 structure. We then concluded that the target selectivity and the influence on G4 RNA structure differed between TDP‐43 and FUS.

ModE is the molybdate-sensing transcription regulator that controls the expression of genes related to molybdate homeostasis in Escherichia coli . ModE is activated by binding molybdate and acts as both an activator and a repressor. By genomic systematic evolution of ligands by exponential enrichment (SELEX) screening and promoter reporter assays, we have identified a total of nine operons, including the hitherto identified modA , moaA , dmsA , and napF operons, of which six were activated by ModE and three were repressed. In addition, two promoters were newly identified and direct transcription of novel genes, referred to as morA and morB , located on antisense strands of yghW and torY , respectively. The morA gene encodes a short peptide, MorA, with an unusual initiation codon. Surprisingly, overexpression of the morA 5′ untranslated region exhibited an inhibitory influence on colony formation of E. coli K-12.