The structural and functional organization of the ribosomal RNA gene cluster and the full-length R2 non-LTR retrotransposon (integrated into a specific site of 28S ribosomal RNA genes) of the German cockroach, , is described. A partial sequence of the R2 retrotransposon of the cockroach is also analyzed. The analysis of previously published next-generation sequencing data from the genome reveals a new type of retrotransposon closely related to R2 retrotransposons but with a random distribution in the genome. Phylogenetic analysis reveals that these newly described retrotransposons form a separate clade. It is shown that proteins corresponding to the open reading frames of newly described retrotransposons exhibit unequal structural domains. Within these retrotransposons, a recombination event is described. New mechanism of transposition activity is discussed. The essential structural features of R2 retrotransposons are conserved in cockroaches and are typical of previously described R2 retrotransposons. However, the investigation of the number and frequency of 5'-truncated R2 retrotransposon insertion variants in eight populations suggests recent mobile element activity. It is shown that the pattern of 5'-truncated R2 retrotransposon copies can be an informative molecular genetic marker for revealing genetic distances between insect populations.
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http://dx.doi.org/10.3390/genes11101202 | DOI Listing |
Nucleic Acids Res
January 2025
Department of Microbiology, Icahn School of Medicine at Mount Sinai, NY, NY 10029, USA.
Human endogenous retroviruses (HERVs) occupy a large portion of the human genome. Most HERVs are transcriptionally silent, but they can be reactivated during pathological states such as viral infection and certain cancers. The HERV-K HML-2 clade includes elements that recently integrated have in the human germ line and often contain intact open reading frames that possibly support peptide and protein expression.
View Article and Find Full Text PDFGenes Cells
January 2025
Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, Japan.
The dysfunction of the innate immune system is well-described as a clinical characteristic of COVID-19. While several groups have reported human endogenous retroviruses (ERVs) as enhancing factors of immune reactivity, characterization of the COVID-19-specific ERVs has not yet been sufficiently conducted. Here, we revealed the transcriptome profile of more than 500 ERV subfamilies and innate immune response genes in eight different cohorts of platelet, peripheral blood mononuclear cells (PBMCs), lung, frontal cortex of brain, ventral midbrain, pooled human umbilical vein endothelial cells (pHUVECs), placenta, and cardiac microvascular endothelial cells (HCMEC) from COVID-19 patients (total; n = 124) and normal samples (total; n = 53) using publicly available datasets.
View Article and Find Full Text PDFCurr Environ Health Rep
January 2025
Institute for Society and Genetics, University of California, Boyer Hall, Room 332, 611 Charles E Young Dr E., UCLA, Los Angeles, CA, 90095, USA.
Purpose Of Review: The burgeoning field of environmental epigenetics has revealed the malleability of the epigenome and uncovered numerous instances of its sensitivity to environmental influences; however, pinpointing specific mechanisms that tie together environmental triggers, epigenetic pathways, and organismal responses has proven difficult. This article describes how Caenorhabditis elegans can fill this gap, serving as a useful model for the discovery of molecular epigenetic mechanisms that are conserved in humans.
Recent Findings: Recent results show that environmental stressors such as methylmercury, arsenite, starvation, heat, bacterial infection, and mitochondrial inhibitors can all have profound effects on the epigenome, with some insults showing epigenetic and organismal effects for multiple generations.
Plants (Basel)
December 2024
A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia.
Among the long non-coding RNAs that are currently recognized as important regulatory molecules influencing a plethora of processes in eukaryotic cells, circular RNAs (circRNAs) represent a distinct class of RNAs that are predominantly produced by back-splicing of pre-mRNA. The most studied regulatory mechanisms involving circRNAs are acting as miRNA sponges, forming R-loops with genomic DNA, and encoding functional proteins. In addition to circRNAs generated by back-splicing, two types of circRNAs capable of autonomous RNA-RNA replication and systemic transport have been described in plants: viroids, which are infectious RNAs that cause a number of plant diseases, and retrozymes, which are transcripts of retrotransposon genomic loci that are capable of circularization due to ribozymes.
View Article and Find Full Text PDFNat Commun
January 2025
Biological Sciences, North Dakota State University, Fargo, USA.
Horizontal transfer of genetic material in eukaryotes has rarely been documented over short evolutionary timescales. Here, we show that two retrotransposons, Shellder and Spoink, invaded the genomes of multiple species of the melanogaster subgroup within the last 50 years. Through horizontal transfer, Spoink spread in D.
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