Biology subjects

Taneja, A.

Publications and source records attributed to Taneja, A..

3 recordsLinked to original sources

bioRxiv2026

PARP6-dependent vimentin ADP-ribosylation prevents myofibroblast activation in cardiac fibrosis

Cardiac fibrosis is a central driver of adverse remodeling during heart failure, yet the post-translational regulation of myofibroblast activation remains poorly defined. Here, we identified PARP6 as a mono-ADP-ribosyltransferase that repressed myofibroblast activation through the ADP-ribosylation of vimentin. PARP6 expression was reduced in failing human hearts and Parp6 haploinsufficiency in mice was sufficient to induce cardiac fibrosis. At the cellular level, PARP6 ADP-ribosylated vimentin thereby limiting actin stress fiber formation. Mechanistically, PARP6 inhibition enhanced RhoA activation and vimentin-RhoA complex formation, thus activating the RhoA-ROCK-LIMK-cofilin pathway. Consistently, Parp6 haploinsufficiency was associated with increased cofilin phosphorylation in mice hearts. In primary cardiac fibroblasts, PARP6 inhibition promoted RhoA-dependent actin stress fiber accumulation and induced myofibrotic protein expression. Together, these findings define a PARP6-vimentin(ADP-ribosylation)-RhoA axis that restrained contractility-driven fibroblast activation, indicating a cardioprotective role of PARP6 with potential therapeutic relevance for fibrotic heart disease.

molecular biology↗

bioRxiv2022

Harmonin homology domains of human RTEL1 interact with replication protein A and DNA

The regulator of telomere elongation helicase 1 (RTEL1) is an Fe-S cluster containing helicase that plays important roles in telomere DNA maintenance, DNA repair, and genome stability. It is a modular protein comprising a helicase domain, two tandem harmonin homology domains 1 & 2 (HHD1 and HHD2), and a Zn2+ binding RING domain. In this study, we have unravelled a novel interaction between RTEL1 and replication protein A (RPA) and shown their co-localization upon DNA damage in the cells. Using NMR spectroscopy, we show that 32C domain of RPA and DNA competitively bind with HHD2 of RTEL1. To understand the structural basis of HHD2 - 32C and HHD2 - DNA interactions, we have determined a 1.6 [A] resolution crystal structure of HHD2. NMR chemical shift perturbations-based mapping revealed the 32C and DNA binding surface on HHD2 of RTEL1. Together, these results establish an interplay among RTEL1, RPA, and DNA that provide mechanistic insights into the RTEL1 recruitment at DNA during the processes of replication, repair, and recombination.

biophysics↗

bioRxiv2017

Labeling of prokaryotic mRNA in live cells using fluorescent in situ hybridization of transcript-annealing molecular beacons (FISH-TAMB)

High-throughput sequencing and cellular imaging have expanded our knowledge of microbial diversity and expression of cellular activity. However, it remains challenging to characterize low-abundance, slow-growing microorganisms that play key roles in biogeochemical cycling. With the goal of isolating transcriptionally active cells of these microorganisms from environmental samples, we developed fluorescent in situ hybridization of transcript-annealing molecular beacons (FISH-TAMB) to label living prokaryotic cells. FISH-TAMB utilizes polyarginine cell-penetrating peptides to deliver molecular beacons across cell walls and membranes. Target cells are fluorescently labeled via hybridization between molecular beacons and messenger RNA of targeted functional genes. FISH-TAMBs target specificity and deliverance into both bacterial and archaeal cells were demonstrated by labeling intracellular methyl-coenzyme M reductase A (mcrA) transcripts expressed by Escherichia coli mcrA+, Methanosarcina barkeri, and a methanogenic enrichment of deep continental fracture fluid. Growth curve analysis supported sustained cellular viability following FISH-TAMB treatment. Flow cytometry and confocal microscopy detected labeled single cells and single cells in aggregates with unlabeled cells. As FISH-TAMB is amenable to target any functional gene of interest, when coupled with cell sorting, imaging, and sequencing techniques, FISH-TAMB will enable characterization of key uncharacterized rare biosphere microorganisms and of the syntrophically activated metabolic pathways between physically associated microorganisms.

microbiology↗