Create accountLogin

Recent searches

No recent searches

Search options

Only available when logged in.
paquita.masto.host is one of the many independent Mastodon servers you can use to participate in the fediverse.
Esta es una instancia feminista, antifascista, antirracista y LGTBIQ-friendly que lucha activamente contra el acoso a sus usuarios y usuarias en todas sus formas, explícitas e implícitas.

Administered by:

Server stats:

435
active users

paquita.masto.host: AboutProfiles directoryPrivacy policy

Mastodon: AboutGet the appKeyboard shortcutsView source codev4.3.7

#tes

5 posts3 participants0 posts today
Public
Amelia Cervera 🧬

A family of Tn7-like transposons evolved to target CRISPR repeats.
#Transposons #TEs #Tn7 #CRISPR #Preprint
biorxiv.org/content/10.1101/20

bioRxiv · A family of Tn7-like transposons evolved to target CRISPR repeatsTn7 family transposons are mobile genetic elements known for precise target site selection, with some co-opting CRISPR-Cas systems for RNA-guided transposition. We identified a novel group of Tn7-like transposons in Cyanobacteria that preferentially target CRISPR arrays, suggesting a new functional interaction between these elements and CRISPR-Cas systems. Using bioinformatics tools, we characterized their phylogeny, target specificity, and sub-specialization. The array-targeting elements are phylogenetically close to tRNA-targeting elements. The distinct target preference coincides with loss of a C-terminal region in the TnsD protein which is responsible for recognizing target sites when compared to closely related elements. Notably, elements are found integrated into a fixed position within CRISPR spacer regions, a behavior that might minimize negative impacts on the host defense system. These transposons were identified in both plasmid and genomic CRISPR arrays, indicating that their preferred target provides a means for both safe insertion in the host chromosome and a mechanism for dissemination. Attempts to reconstitute these elements in E. coli were unsuccessful, indicating possible dependence on native host factors. Our findings expand the diversity of interactions between Tn7-like transposons and CRISPR systems. ### Competing Interest Statement The authors have declared no competing interest.
Public
Amelia Cervera 🧬

Multi-tissue characterization of the constitutive heterochromatin proteome in Drosophila identifies a link between satellite DNA organization and transposon repression.
#SatelliteDNA #Centromers #Chromocenters #piRNA #Transposons #TEs #Drosophila
journals.plos.org/plosbiology/

journals.plos.orgMulti-tissue characterization of the constitutive heterochromatin proteome in Drosophila identifies a link between satellite DNA organization and transposon repressionPericentromeric heterochromatin clusters into nuclear foci known as chromocenters, the proteome of which remains largely unknown. This study uses quantitative mass spectrometry to characterize the chromocenter-associated proteome in multiple tissues, identifying a link between satellite DNA-binding proteins and transposon repression during embryogenesis.
Public *
Amelia Cervera 🧬

Elevated expression of the retrotransposon LINE-1 drives Alzheimer’s disease-associated microglial dysfunction.

#Transposons #TEs #Alzheimer #LOAD #LINE1 #Microglia

link.springer.com/article/10.1

SpringerLinkElevated expression of the retrotransposon LINE-1 drives Alzheimer’s disease-associated microglial dysfunction - Acta NeuropathologicaAberrant activity of the retrotransposable element long interspersed nuclear element-1 (LINE-1) has been hypothesized to contribute to cellular dysfunction in age-related disorders, including late-onset Alzheimer’s disease (LOAD). However, whether LINE-1 is differentially expressed in cell types of the LOAD brain, and whether these changes contribute to disease pathology is largely unknown. Here, we examined patterns of LINE-1 expression across neurons, astrocytes, oligodendrocytes, and microglia in human postmortem prefrontal cortex tissue from LOAD patients and cognitively normal, age-matched controls. We report elevated immunoreactivity of the open reading frame 1 protein (ORF1p) encoded by LINE-1 in microglia from LOAD patients and find that this immunoreactivity correlates positively with disease-associated microglial morphology. In human iPSC-derived microglia (iMG), we found that CRISPR-mediated transcriptional activation of LINE-1 drives changes in microglial morphology and cytokine secretion and impairs the phagocytosis of amyloid beta (Aβ). We also find LINE-1 upregulation in iMG induces transcriptomic changes genes associated with antigen presentation and lipid metabolism as well as impacting the expression of many AD-relevant genes. Our data posit that heightened LINE-1 expression may trigger microglial dysregulation in LOAD and that these changes may contribute to disease pathogenesis, suggesting a central role for LINE-1 activity in human LOAD.
Public *
Amelia Cervera 🧬

The complete genome assembly of Nicotiana benthamiana reveals the genetic and epigenetic landscape of centromeres.

#Nicotiana #Centromeres #Transposons #TEs #Satellites #GenomeAssembly

nature.com/articles/s41477-024

www.nature.comThe complete genome assembly of Nicotiana benthamiana reveals the genetic and epigenetic landscape of centromeres | Nature PlantsNicotiana benthamiana is a model organism widely adopted in plant biology. Its complete assembly remains unavailable despite several recent improvements. To further improve its usefulness, we generate and phase the complete 2.85 Gb genome assembly of allotetraploid N. benthamiana. We find that although Solanaceae centromeres are widely dominated by Ty3/Gypsy retrotransposons, satellite-based centromeres are surprisingly common in N. benthamiana, with 11 of 19 centromeres featured by megabase-scale satellite arrays. Interestingly, the satellite-enriched and satellite-free centromeres are extensively invaded by distinct Gypsy retrotransposons which CENH3 protein more preferentially occupies, suggestive of their crucial roles in centromere function. We demonstrate that ribosomal DNA is a major origin of centromeric satellites, and mitochondrial DNA could be employed as a core component of the centromere. Subgenome analysis indicates that the emergence of satellite arrays probably drives new centromere formation. Altogether, we propose that N. benthamiana centromeres evolved via neocentromere formation, satellite expansion, retrotransposon enrichment and mtDNA integration. This study generates and phases the complete genome assembly of a model plant Nicotiana benthamiana, revealing insights into the structure, epigenetic landscape and evolutionary dynamics of its centromeres following allotetraploidization.
ExploreLive feeds
About