Biology subjects

Tewari, H.

Publications and source records attributed to Tewari, H..

3 recordsLinked to original sources

bioRxiv2026

Global effects of the guanine quadruplex binding ligands Pyridostatin and TMPyP4 on microRNA regulation in response to ionizing radiation in HeLa cells

Guanine quadruplexes (G4s) are secondary structures in DNA and RNA that regulate a wide range of biological processes. Small molecules that assist in formation, stabilization or destabilization of G4s indirectly alter the cellular functions governed by these structures. Pyridostatin (PDS) and TMPyP4 are two well-characterized G4-binding ligands that have been shown to modulate various cellular functions, particularly in cancer cells. However, their effects on microRNAs (miRNAs), which are key regulators of post-transcriptional gene expression, remain poorly understood. HeLa cells treated either with PDS or TMPyP4 and gamma radiation were subjected to small RNA sequencing. Analysis results revealed a higher overall small RNA content in PDS treated cells, whereas TMPyP4 treated cells exhibited a greater number of differentially expressed miRNAs following gamma radiation exposure. Target gene analysis of the top differentially regulated miRNAs revealed that molecular functions related to DNA/nucleic acid binding activities of various factors, including RNA polymerase II cis-regulatory region sequence-specific binding activity, were largely affected. Furthermore, KEGG pathway enrichment studies suggested that observed changes may result from alterations in signal transduction pathways in cells treated with G4 ligands and gamma radiation compared to untreated control cells. Additionally, G4 ligand treatment altered the cellular expression levels of histone modifying enzymes, including histone deacetylases and methyltransferases. This finding suggest that the two G4 binding ligands- PDS and TMPyP4 differentially regulate miRNA expression profiles, histone modifying enzymes and associated biological pathways in HeLa cells.

cancer biology↗

bioRxiv2025

In vivo guanine quadruplex structure dynamics and role in genome maintenance in Deinococcus radiodurans

Guanine quadruplex (G4) structures are secondary structures formed in nucleic acids that are rich in guanine bases. G4 structures regulate various cellular processes both in eukaryotes and prokaryotes. Deinococcus radiodurans, an extremophile show sensitivity to ionizing radiation in the presence of G4 binding ligands during the post-irradiation recovery period (PIR). Putative G4 motifs positioned at different locations on the genes fold into different topologies in vitro in the presence of monovalent cations while divalent cation Mg+2 supported the stable G4 formation but Mn+2 destabilizes the G4 structures. Thioflavin T and anti-DNA quadruplex antibodies detected the in vivo formation and dynamics of G4 structure in response to various DNA damaging agents, more in the presence of gamma radiation treatment. G4 binding drugs during PIR arrested the G4 structure dynamics and delayed the DNA repair process. Further, the absence of G4 helicase, RecQ resulted in the accumulation of more G4 structures and genome instability. All these results indicate that the guanine quadruplex structure formation increases in response to cellular stress and G4s are crucial for stable genome maintenance in Deinococcus radiodurans.

microbiology↗

bioRxiv2020

Understanding pigeon pea (Cajanus cajan) production conditions, stakeholders preferences for varietal traits and their implications for breeding programmes in India

Pigeon pea (Cajanus cajan) is an important pulse crop in the Indian diet and one of the most important sources of dietary protein for the population. In the context of the fourth phase of the Indo-Swiss Collaboration in Biotechnology, an assessment how farmers and consumers perceive new pigeon pea cultivars and what are their preferred traits was conducted. This investigation assessed Indias food security implications due to stagnating and low yield of pigeon pea and ascertain farmers preferences of pigeon pea varietal traits, production constraints and farmers coping strategies in diverse pigeon pea production environments. Results indicated that production constraints in the studied regions were basically similar, with majority of the farmers identifying pod borer & pod fly as the major pest, and wilt as the major disease and drought as a major production constraint. Farmers indicated the use of clean seed, high yielding varieties, inter & mixed cropping, planting density, and manure application as some of the strategies they used to cope with the production constraints. In terms of preference for new cultivars, farmers want high grain yield with drought tolerance, medium to early maturity, pod borer resistance, tolerance to wilt disease, moderate plant height and ease of threshing without compromising other preferred attributes. The analysis of processors preference of grain types for dal processing showed that uniform size, oval shape, orange coloured seed and most importantly moderately hard seed coat are highly desirable. Consumers lacked awareness on the varieties, but considered traits like uniform seeds and reduced cooking time traits more desirable.

ecology↗