Publications by authors named "Sergei S Ryazansky"

Background: Understanding genome organization and evolution is important for species involved in transmission of human diseases, such as mosquitoes. Anophelinae and Culicinae subfamilies of mosquitoes show striking differences in genome sizes, sex chromosome arrangements, behavior, and ability to transmit pathogens. However, the genomic basis of these differences is not fully understood.

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  • The nascent polypeptide-associated complex (NAC) is a crucial ribosome-associated protein involved in protein folding and sorting, and it is conserved across eukaryotic organisms.
  • Researchers have identified germline-specific NACαβ paralogs (gNACs), which have unique protein structures in their α and β subunits, particularly longer regions that may be phosphorylated.
  • The study suggests that these gNACs play a role in the coordination of protein regulation within germline cells, and there appears to be an interaction between gNACs and the commonly expressed NAC subunits that impacts organismal development.
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Genomic disorders, the syndromes with multiple manifestations, may occur sporadically due to unequal recombination in chromosomal regions with specific architecture. Therefore, each patient may carry an individual structural variant of DNA sequence (SV) with small insertions and deletions (INDELs) sometimes less than 10 bp. The transposable elements of the Tc1/ superfamily are often associated with hotspots for homologous recombination involved in human genetic disorders, such as Williams Beuren Syndromes (WBS) with LIM-kinase 1-dependent cognitive defects.

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Piwi in a complex with Piwi-interacting RNAs (piRNAs) triggers transcriptional silencing of transposable elements (TEs) in Drosophila ovaries, thus ensuring genome stability. To do this, Piwi must scan the nascent transcripts of genes and TEs for complementarity to piRNAs. The mechanism of this scanning is currently unknown.

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  • The RNA helicase Spindle-E (Spn-E) is crucial for the piRNA silencing process in Drosophila, specifically in the reproductive organs where it helps prevent retrotransposon mobilization and gene derepression.* -
  • Research on spn-E heterozygous flies showed a significant presence of piRNA ping-pong pairs linked to Su(Ste) transcripts, but these levels dropped sharply in spn-E mutant flies.* -
  • The absence of Spn-E led to a notable decrease in key proteins involved in the ping-pong mechanism, Aubergine and AGO3, suggesting that Spn-E might play a role in post-transcriptional regulation rather than affecting their overall synthesis.*
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The testis specific X-linked genes whose evolution is traced here in the melanogaster species subgroup are thought to undergo fast rate of diversification. The CK2ßtes and NACβtes gene families encode the diverged regulatory β-subunits of protein kinase CK2 and the homologs of β-subunit of nascent peptide associated complex, respectively. We annotated the CK2βtes-like genes related to CK2ßtes family in the D.

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Proteins of the PIWI subfamily Aub and AGO3 associated with the germline-specific perinuclear granules (nuage) are involved in the silencing of retrotransposons and other selfish repetitive elements in the Drosophila genome. PIWI proteins and their 25- to 30-nt PIWI-interacting RNA (piRNAs) are considered as key participants of the piRNA pathway. Using immunostaining, we found a large, nuage-associated organelle in the testes, the piNG-body (piRNA nuage giant body), which was significantly more massive than an ordinary nuage granule.

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  • MicroRNAs (miRNAs) are small RNA molecules that can inhibit the translation of specific messenger RNAs, with many found in clusters within the Drosophila genome.
  • Research has shown that while most clustered miRNAs have similar expression patterns across different tissues, some demonstrate uncoordinated expression, indicating that they may be regulated differently.
  • The discovery of only upstream promoters in these uncoordinated miRNA clusters suggests they are transcribed as single units, and the differing expression profiles imply potential post-transcriptional regulation affecting their stability or processing.
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