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Rajachandran, S.

Publications and source records attributed to Rajachandran, S..

2 recordsLinked to original sources

Subcellular Level Spatial Transcriptomics with PHOTON

The subcellular localization of RNA is closely linked to its function. Many RNA species are partitioned into organelles and other subcellular compartments for storage, processing, translation, or degradation. Thus, capturing the subcellular spatial distribution of RNA would directly contribute to the understanding of RNA functions and regulation. Here, we present PHOTON (Photoselection of Transcriptome over Nanoscale), a method which combines high resolution imaging with high throughput sequencing to achieve spatial transcriptome profiling at subcellular resolution. We demonstrate PHOTON as a versatile tool to accurately capture the transcriptome of target cell types in situ at the tissue level such as granulosa cells in the ovary, as well as RNA content within subcellular compartments such as the nucleolus and the stress granule. Using PHOTON, we also reveal the functional role of m6A modification on mRNA partitioning into stress granules. These results collectively demonstrate that PHOTON is a flexible and generalizable platform for understanding subcellular molecular dynamics through the transcriptomic lens.

genomics↗

Functional and Clinical Implications of Extrachromosomal Circular DNA in the Human Germline

Extrachromosomal circular DNA (eccDNA) originates from linear chromosomal DNA and can be found in various human cell types including the male germline. However, the functional effects and biogenesis mechanisms of the eccDNA in the human male germline are not well understood. Here, we developed a sequencing approach to extract eccDNA sequence information and the paired transcriptome information from the same cells. By applying this approach to human samples, we found evidence of transcriptional activities of germline eccDNAs. We also showed that patients with chronic diseases such as hypertension and diabetes had a significantly higher number of eccDNAs in the sperm than their healthy counterparts. This was, at least partly, due to an increased apoptosis signaling in the germline. Analysis of single cell RNA sequencing data of spermatogenic cells from diabetic patients vs. healthy individuals suggested that a dysregulation in the expression levels of multiple poly (ADP-ribose) polymerases may contribute to the increased amount of germline eccDNAs in diseased patients. In addition, we identified a potential horizontal transfer mechanism through which healthy sperm can take up eccDNAs from their surrounding microenvironment. Together, our results suggest that eccDNA may have functional effects on the germline, and it may serve as a non-invasive clinical biomarker for human health.

genomics↗