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Biology subjects

Maracci, C.

Publications and source records attributed to Maracci, C..

2 recordsLinked to original sources

Tissue-specific regulation of translational readthrough tunes functions of the Traffic Jam transcription factor

Translational readthrough (TR) occurs when the ribosome decodes a stop codon as a sense codon, resulting in two protein isoforms synthesized from the same mRNA. TR is pervasive in eukaryotic organisms; however, its biological significance remains unclear. In this study, we quantify the TR potential of several candidate genes in Drosophila melanogaster and characterize the regulation of TR in the large Maf transcription factor Traffic jam (Tj). We used CRISPR/Cas9 generated mutant flies to show that the TR-generated Tj isoform is expressed in the nuclei of a subset of neural cells of the central nervous system and is excluded from the somatic cells of gonads, which express the short Tj isoform only. Translational control of TR is critical for preservation of neuronal integrity and maintenance of reproductive health. Fine-tuning of the gene regulatory functions of transcription factors by TR provides a new potential mechanism for cell-specific regulation of gene expression. HighlightsO_LITj undergoes tissue-specific TR in neural cells of the central nervous system. C_LIO_LIStrict control of TR is crucial for neuroprotection and maintenance of reproductive capacity. C_LIO_LITR selectively fine-tunes the gene regulatory functions of the transcription factor. C_LIO_LITR in Tj links transcription and translation of tissue-specific control of gene expression. C_LI O_FIG O_LINKSMALLFIG WIDTH=197 HEIGHT=200 SRC="FIGDIR/small/411694v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@1e6fb7dorg.highwire.dtl.DTLVardef@188d5c0org.highwire.dtl.DTLVardef@894173org.highwire.dtl.DTLVardef@127f4ae_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

Dynamics of ribosomes and release factors during translation termination in E. coli

Release factors RF1 and RF2 promote hydrolysis of peptidyl-tRNA during translation termination. The GTPase RF3 promotes recycling of RF1 and RF2. Using single molecule FRET together with ensemble kinetics, we show that ribosome termination complexes that carry two factors, RF1-RF3 or RF2-RF3, are dynamic and fluctuate between non-rotated and rotated states, while each factor alone has its distinct signature on the ribosome dynamics and conformation. Dissociation of RF1 depends on peptide release and the presence of RF3, whereas RF2 can dissociate spontaneously. RF3 binds in the GTP-bound state and can rapidly dissociate without GTP hydrolysis from termination complex carrying RF1. GTP cleavage helps RF3 release from ribosomes stalled in the rotated state in the absence of RF1. Our data suggest how the stochastic assembly of the ribosome-RF1-RF3-GTP complex, peptide release, and ribosome fluctuations promote termination of protein synthesis and recycling of the release factors.

biochemistry↗