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Krishnan, K. S.

Publications and source records attributed to Krishnan, K. S..

2 recordsLinked to original sources

Integrated transcriptomics and proteomics define the TRP channel hierarchy in mouse cortex

Transient receptor potential (TRP) channels are evolutionarily conserved polymodal cation channels that mediate diverse sensory functions across the animal kingdom. Although TRP channels play key roles in peripheral sensation, their expression and functional relevance in the cerebral cortex remain poorly defined. Here, we integrate long- and short-read transcriptomics, targeted qPCR and membrane-aware proteomics to quantify TRP family members in adult mouse cortex. Across transcriptomic platforms, cortical TRP expression is dominated by TRPML, TRPC, and TRPM subfamilies, with lower representation of TRPP/TRPV, whereas Trpa1 and Trpv1 lie near empirical detection thresholds. Our proteomic workflow yields reproducible protein-level evidence for a subset of cortical TRPs, including TRPV2, TRPC4, TRPM3, TRPM7 and TRPP2, consistent with transcript rank order, while TRPA1/TRPV1 do not meet replicate-level protein-group detection criteria under 1% FDR control. Together, these multi-platform measurements establish a quantitative reference for cortical TRP biology and a framework for profiling low-abundance ion channels in complex brain tissue.

molecular biology↗

Single-molecule multimodal timing of in vivo mRNA synthesis

mRNA synthesis requires extensive pre-mRNA maturation, the organisation of which remains unclear. Here, we directly sequence pre-mRNA without metabolic labelling or amplification to resolve transcription and multimodal pre-mRNA processing at single-molecule resolution. Using poly(A) tail measurement, we distinguish transcriptionally engaged pre-mRNA from polyadenylated transcripts, revealing that splicing is substantially delayed compared to previous estimates. Splicing is rare for at least 10 kb behind elongating RNA polymerase II such that thousands of genes remain largely unspliced during transcription, revising the notion that splicing is predominantly co-transcriptional. Progressive splicing becomes apparent only on polyadenylated transcripts, suggesting that splicing is commonly activated after 3' end formation. Unexpectedly, we find abundant m6A on unspliced pre-mRNA, indicating that a substantial portion of RNA methylation precedes splicing. This m6A methylation is suppressed around exon boundaries, indicating that m6A topology is established prior to exon junction complex deposition. Finally, we demonstrate that 3' end cleavage occurs multiple kilobases behind transcription in coordination with efficient transcription termination, and further highlight recursive 3' end formation across hundreds of genes. Conserved from human cells to mouse tissues, we illustrate a revised timeline for mRNA synthesis wherein cleavage, termination, and m6A deposition occur earlier than, or at least partially decoupled from, the bulk of splicing, reframing the sequence of early mammalian gene expression.

genomics↗