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Mapping the proteome of Drosophila melanogaster: analysis of embryos and adult heads by LC-IMS-MS methods.

Multidimensional separations combined with mass spectrometry are used to study the proteins that are present in two states of Drosophila melanogaster: the whole embryo and the adult head. The approach includes the incorporation of a gas-phase separation dimension in which ions are dispersed according to differences in their mobilities and is described as a means of providing a detailed analytical map of the proteins that are present. Overall, we find evidence for 1133 unique proteins. In total, 780 are identified in the head, and 660 are identified in the embryo. Only 307 proteins are in common to both developmental stages, indicating that there are significant differences in these proteomes. A comparison of the proteome to a database of mRNAs that are found from analysis by cDNA approaches (i.e., transcriptome) also shows little overlap. All of this information is discussed in terms of the relationship between the predicted genome, and measured transcriptomes and proteomes. Additionally, the merits and weaknesses of current technologies are assessed in some detail.

Animals↗

Deus ex genomix.

Explore the source record for details and available documents.

Animals↗

Characterization of the Drosophila melanogaster genome at the nuclear lamina.

The nuclear lamina binds chromatin in vitro and is thought to function in its organization, but genes that interact with it are unknown. Using an in vivo approach, we identified approximately 500 Drosophila melanogaster genes that interact with B-type lamin (Lam). These genes are transcriptionally silent and late replicating, lack active histone marks and are widely spaced. These factors collectively predict lamin binding behavior, indicating that the nuclear lamina integrates variant and invariant chromatin features. Consistently, proximity of genomic regions to the nuclear lamina is partly conserved between cell types, and induction of gene expression or active histone marks reduces Lam binding. Lam target genes cluster in the genome, and these clusters are coordinately expressed during development. This genome-wide analysis gives clear insight into the nature and dynamic behavior of the genome at the nuclear lamina, and implies that intergenic DNA functions in the global organization of chromatin in the nucleus.

Animals↗

Biological function of unannotated transcription during the early development of Drosophila melanogaster.

Many animal and plant genomes are transcribed much more extensively than current annotations predict. However, the biological function of these unannotated transcribed regions is largely unknown. Approximately 7% and 23% of the detected transcribed nucleotides during D. melanogaster embryogenesis map to unannotated intergenic and intronic regions, respectively. Based on computational analysis of coordinated transcription, we conservatively estimate that 29% of all unannotated transcribed sequences function as missed or alternative exons of well-characterized protein-coding genes. We estimate that 15.6% of intergenic transcribed regions function as missed or alternative transcription start sites (TSS) used by 11.4% of the expressed protein-coding genes. Identification of P element mutations within or near newly identified 5' exons provides a strategy for mapping previously uncharacterized mutations to their respective genes. Collectively, these data indicate that at least 85% of the fly genome is transcribed and processed into mature transcripts representing at least 30% of the fly genome.

Amino Acid Sequence↗

Genomic and functional evolution of the Drosophila melanogaster sperm proteome.

In addition to delivering a haploid genome to the egg, sperm have additional critical functions, including egg activation, origination of the zygote centrosome and delivery of paternal factors. Despite this, existing knowledge of the molecular basis of sperm form and function is limited. We used whole-sperm mass spectrometry to identify 381 proteins of the Drosophila melanogaster sperm proteome (DmSP). This approach identified mitochondrial, metabolic and cytoskeletal proteins, in addition to several new functional categories. We also observed nonrandom genomic clustering of sperm genes and underrepresentation on the X chromosome. Identification of widespread functional constraint on the proteome indicates that sexual selection has had a limited role in the overall evolution of D. melanogaster sperm. The relevance of the DmSP to the study of mammalian sperm function and fertilization mechanisms is demonstrated by the identification of substantial homology between the DmSP and proteins of the mouse axoneme accessory structure.

Animals↗

The first chromosome-level genome of the lappet moth Trabala vishnou (Lepidoptera: Lasiocampidae).

Trabala vishnou (Lefèbvre, 1827) (Lepidoptera: Lasiocampidae) is a destructive leaf-eating pest that causes severe damage to forest ecosystems, leading to substantial economic losses. Herein, we sequenced and assembled a high-quality chromosome-level genome of T. vishnou using a combination of Illumina reads, PacBio HiFi reads, and High throughput Chromosome Conformation Capture (Hi-C) technologies. The genome size is 561.86 Mb and spans 25 chromosomes, exhibiting a high level of contiguity (scaffold/contig N50 = 21.75 Mb/20.67 Mb). Benchmarking Universal Single-Copy Orthologs (BUSCO) analysis a 99.5% completeness score for this genome assembly. Repeat elements constitute 62.66% of the genome. A total of 1,630 non-coding RNAs and 12,895 protein-coding genes have been identified within the genome. The first chromosome-level genome of T. vishnou serves as a valuable reference for elucidating the evolution of functional traits in Lasiocampidae family and will facilitate the development of strategies for controlling defoliating pests.

Animals↗

Chromosome-level genome assembly of the longhorn beetle Arhopalus rusticus (Coleoptera: Cerambycidae).

The longhorn beetle Arhopalus rusticus (Coleoptera: Cerambycidae) is a widely distributed wood-boring pest of conifers. Here, we assembled a chromosome-level genome of A. rusticus using Illumina, Oxford Nanopore, and Hi-C sequencing technologies. The assembled genome is 1180.40 Mb, with a scaffold N50 of 125.01 Mb, and BUSCO completeness of 93.6%. All contigs were assembled into ten pseudo-chromosomes. The genome contains 69.87% repeat sequences. We identify 18, 377 protein-coding genes in the genome, of which 11,368 were functionally annotated. This genome provides a valuable resource for understanding the ecology, genetics, and evolution of A. rusticus, as well as for controlling wood-boring pests.

Animals↗

Chromosome-level genome assembly of the large carpenter bee Xylocopa dejeanii Lepeletier, 1841 (Hymenoptera: Apidae).

Xylocopinae, a diverse bee subfamily comprising over 1,000 bee species, and also a major model system for studying the pollination and evolution of sociality. The lack of chromosome-level genome assembly resources for the Xylocopinae limits our research of their biology and evolution. Here, we provided the first pseudo-chromosomes genome assembly of the Xylocopa dejeanii combined PacBio CLR long reads, Illumina sequences, and Hi-C data. The final genome is 194.44 Mb located in 16 chromosomes. Our assembly includes 141 scaffolds, with a scaffold N50 length of 13.15 Mb. BUSCO analysis revealed 99.00% completeness. Genome annotation identified 28.27 Mb of repetitive elements, 10,970 protein-coding genes, and 432 ncRNAs. This high-quality X. dejeanii assembly advances our understanding of Xylocopinae genomics and provides new insights into bee evolution.

Animals↗

Frequency and fitness cost of resistance to Bacillus thuringiensis in Chrysomela tremulae (Coleoptera: Chrysomelidae).

The "high dose-refuge" (HDR) strategy is commonly recommended and currently used for delaying or preventing pest adaptation to transgenic plants producing Bacillus thuringiensis (Bt) toxins. The efficiency of this strategy depends, among other factors, on the initial frequency of Bt resistance alleles and on the fitness costs associated with these alleles. Two years ago, an allele conferring resistance to Bt poplar was detected in a French population of the poplar pest Chrysomela tremulae F. Although this pest had never been subjected to Bt selection pressure due to human activities, the frequency of this allele was estimated at 0.0037, with a 95% credible (CI) interval of 0.00045-0.0080. We investigated the frequency of this allele in a second sample of C. tremulae collected more than 500 km from the site of the initial population. The estimated frequency in this sample was 0.0113 (95% CI 0.0031-0.0247), reinforcing the conclusion that resistance to Bt plants may be present at detectable frequencies in pest populations before selection resulting from pest management by humans. The frequency of the Bt resistance allele over the two samples was 0.0049 (95% CI 0.0020-0.0091). We also followed five laboratory lines in which the frequency of this allele was initially fixed at 0.500. After five generations maintained on non-Bt poplar leaves, the frequency of this allele decreased in all lines, whereas allelic frequencies at a neutral locus were unaffected. Thus, the Bt resistance allele detected in French populations of C. tremulae is probably associated with a fitness cost.

Adaptation, Biological↗

Learning to fly--getting the best out of microarrays.

Microarrays are becoming pervasive in biology and can offer unparalleled insights into biological processes. This article suggests that a more considered approach to the design of array probe sequences can substantially improve the technology.

Animals↗

Co-amplification explains linkage disequilibrium of two mosquito esterase genes in insecticide-resistant Culex quinquefasciatus.

The mosquito Culex quinquefasciatus (Say) is a vector of human disease and a world-wide biting nuisance. Organophosphorus insecticides (OPs) have been widely used to control C. quinquefasciatus populations and this has led to the emergence of OP-resistance. Predominantly, resistance is caused by increased production of two non-specific carboxylesterases, Estalpha2(1) and Estbeta2(1). Increased abundance of these esterases is associated with the amplification of their respective genes. The estalpha21 and estbeta21 genes were cloned and sequenced from OP-resistant Sri Lankan C. quinquefasciatus; the two adjacent genes are in a head to head configuration, within a single amplification unit (amplicon). The homology between the two genes suggests that they arose from an ancient duplication event. The two genes have different numbers of exons (estalpha21 has seven and estbeta21 has four); however, the intron/exon boundaries in estbeta21 are all conserved in estalpha21. The two genes are co-amplified in three other mosquito strains with the elevated Estalpha2(1)/Estbeta2(1) phenotype. Their complete linkage disequilibrium is explained by the location of the two genes involved in resistance within a single amplicon. In insecticide-susceptible C. quinquefasciatus, the non-amplified estalpha and estbeta gene loci are also found in a similar head to head configuration, but the size of the intergenic non-coding region is approx. 1 kb less than in the amplicon. The smaller intergenic spacer is also found in a strain with amplified estbeta11, which suggests that extensive laboratory selection for this amplified esterase has not eliminated the non-amplified genes. The intergenic spacer regions have been subcloned and sequenced. They contain numerous possible TATA boxes, promoters and a number of possible regulatory elements with high homology to the consensus sequence of the Barbie box. These latter putative regulatory elements are more numerous in the larger intergenic spacer, which differs from the non-amplified spacer by two large (>>420 bp) and one small (5 bp) insertions.

Amino Acid Sequence↗

Genome-wide identification of mRNAs associated with the translational regulator PUMILIO in Drosophila melanogaster.

Genome-wide identification of RNAs associated with RNA-binding proteins is crucial for deciphering posttranscriptional regulatory systems. PUMILIO is a member of the evolutionary conserved Puf-family of RNA-binding proteins that repress gene expression posttranscriptionally. We generated transgenic flies expressing affinity-tagged PUMILIO under the control of an ovary-specific promoter, and we purified PUMILIO from whole adult flies and embryos and analyzed associated mRNAs by using DNA microarrays. Distinct sets comprising hundreds of mRNAs were associated with PUMILIO at the two developmental stages. Many of these mRNAs encode functionally related proteins, supporting a model for coordinated regulation of posttranscriptional modules by specific RNA-binding proteins. We identified a characteristic sequence motif in the 3'-untranslated regions of mRNAs associated with PUMILIO, and the sufficiency of this motif for interaction with PUMILIO was confirmed by RNA pull-down experiments with biotinylated synthetic RNAs. The RNA motif strikingly resembles the one previously identified for Puf3p, one of five Saccharomyces cerevisiae Puf proteins; however, proteins encoded by the associated mRNAs in yeast and Drosophila do not appear to be related. The results suggest extensive posttranscriptional regulation by PUMILIO and uncover evolutionary features of this conserved family of RNA-binding proteins.

3' Untranslated Regions↗

Genome-wide RNAi screen of Ca(2+) influx identifies genes that regulate Ca(2+) release-activated Ca(2+) channel activity.

Recent studies by our group and others demonstrated a required and conserved role of Stim in store-operated Ca(2+) influx and Ca(2+) release-activated Ca(2+) (CRAC) channel activity. By using an unbiased genome-wide RNA interference screen in Drosophila S2 cells, we now identify 75 hits that strongly inhibited Ca(2+) influx upon store emptying by thapsigargin. Among these hits are 11 predicted transmembrane proteins, including Stim, and one, olf186-F, that upon RNA interference-mediated knockdown exhibited a profound reduction of thapsigargin-evoked Ca(2+) entry and CRAC current, and upon overexpression a 3-fold augmentation of CRAC current. CRAC currents were further increased to 8-fold higher than control and developed more rapidly when olf186-F was cotransfected with Stim. olf186-F is a member of a highly conserved family of four-transmembrane spanning proteins with homologs from Caenorhabditis elegans to human. The endoplasmic reticulum (ER) Ca(2+) pump sarco-/ER calcium ATPase (SERCA) and the single transmembrane-soluble N-ethylmaleimide-sensitive (NSF) attachment receptor (SNARE) protein Syntaxin5 also were required for CRAC channel activity, consistent with a signaling pathway in which Stim senses Ca(2+) depletion within the ER, translocates to the plasma membrane, and interacts with olf186-F to trigger CRAC channel activity.

Animals↗

Comprehensive identification of Drosophila dorsal-ventral patterning genes using a whole-genome tiling array.

Dorsal-ventral (DV) patterning of the Drosophila embryo is initiated by Dorsal, a sequence-specific transcription factor distributed in a broad nuclear gradient in the precellular embryo. Previous studies have identified as many as 70 protein-coding genes and one microRNA (miRNA) gene that are directly or indirectly regulated by this gradient. A gene regulation network, or circuit diagram, including the functional interconnections among 40 Dorsal target genes and 20 associated tissue-specific enhancers, has been determined for the initial stages of gastrulation. Here, we attempt to extend this analysis by identifying additional DV patterning genes using a recently developed whole-genome tiling array. This analysis led to the identification of another 30 protein-coding genes, including the Drosophila homolog of Idax, an inhibitor of Wnt signaling. In addition, remote 5' exons were identified for at least 10 of the approximately 100 protein-coding genes that were missed in earlier annotations. As many as nine intergenic uncharacterized transcription units were identified, including two that contain known microRNAs, miR-1 and -9a. We discuss the potential functions of these recently identified genes and suggest that intronic enhancers are a common feature of the DV gene network.

Animals↗