26 research outputs found

    Hyperexpression of the X Chromosome in Both Sexes Results in Extensive Female Bias of X-Linked Genes in the Flour Beetle

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    A genome's ability to produce two separate sexually dimorphic phenotypes is an intriguing biological mystery. Microarray-based studies of a handful of model systems suggest that much of the mystery can be explained by sex-biased gene expression evolved in response to sexually antagonistic selection. We present the first whole-genome study of sex-biased expression in the red flour beetle, Tribolium castaneum. Tribolium is a model for the largest eukaryotic order, Coleoptera, and we show that in whole-body adults, ∼20% of the transcriptome is differentially regulated between the sexes. Among T. castaneum, Drosophila melanogaster, and Anopheles gambiae, we identify 416 1:1:1 orthologs with conserved sex-biased expression. Overrepresented functional categories among sex-biased genes are primarily those involved in gamete production and development. The genomic distribution of sex-biased genes in T. castaneum is distinctly nonrandom, with the strongest deficit of male-biased genes on the X chromosome (9 of 793) of any species studied to date. Tribolium also shows a significant enrichment of X-linked female-biased genes (408 of 793). Our analyses suggest that the extensive female bias of Tribolium X chromosome gene expression is due to hyperexpression of X-linked genes in both males and females. We propose that the overexpression of X chromosomes in females is an evolutionary side effect of the need to dosage compensate in males and that mechanisms to reduce female X chromosome gene expression to autosomal levels are sufficient but imperfect

    Stereoselective synthesis of novel conformationally restricted β- and γ-amino acids

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    Novel conformationally restricted β- and γ-amino acids containing a cyclopropane ring could be stereoselectively synthesized from readily available 5-methoxyindole and pyridine by copper(I)-catalyzed cyclopropanation with methyl diazoacetate followed by subsequent oxidative cleavage of the resulting adducts

    Stereoselective synthesis of novel conformationally restricted β- and γ-amino acids

    No full text
    Novel conformationally restricted β- and γ-amino acids containing a cyclopropane ring could be stereoselectively synthesized from readily available 5-methoxyindole and pyridine by copper(I)-catalyzed cyclopropanation with methyl diazoacetate followed by subsequent oxidative cleavage of the resulting adducts

    Deprotection of N-alloc amines by Pd(0) /DABCO: an efficient method for in situ peptide coupling of labile amino acids

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    A highly efficient one-pot deprotection/peptide coupling protocol of N-Alloc amino acids with activated N-Boc or N-Fmoc amino acids was developed in solution and on solid phase. DABCO was found to be especially effective for the deprotection of the N-Alloc group, resulting in short reaction times (10–20 min) and allowing the coupling of amino acids that are unstable in unprotected forms

    Posttranslational regulation impacts the fate of duplicated genes

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    Gene and genome duplications create novel genetic material on which evolution can work and have therefore been recognized as a major source of innovation for many eukaryotic lineages. Following duplication, the most likely fate is gene loss; however, a considerable fraction of duplicated genes survive. Not all genes have the same probability of survival, but it is not fully understood what evolutionary forces determine the pattern of gene retention. Here, we use genome sequence data as well as large-scale phosphoproteomics data from the baker’s yeast Saccharomyces cerevisiae, which underwent a whole-genome duplication ∼100 mya, and show that the number of phosphorylation sites on the proteins they encode is a major determinant of gene retention. Protein phosphorylation motifs are short amino acid sequences that are usually embedded within unstructured and rapidly evolving protein regions. Reciprocal loss of those ancestral sites and the gain of new ones are major drivers in the retention of the two surviving duplicates and in their acquisition of distinct functions. This way, small changes in the sequences of unstructured regions in proteins can contribute to the rapid rewiring and adaptation of regulatory networks
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