totalRNA

totalRNA refers to the complete set of ribonucleic acids extracted from a biological sample, encompassing messenger RNA, ribosomal RNA, transfer RNA, and various non‑coding RNA species. This contrasts with isolated mRNA, which is enriched and often purified by methods such as poly(A) selection or rRNA depletion. By retaining all RNA classes, totalRNA provides a comprehensive snapshot of cellular transcriptional activity and RNA content, which is valuable for studies that require analysis of non‑coding RNAs, small RNAs, or rRNA dynamics.

Extraction of totalRNA typically employs guanidinium thiocyanate-phenol-chloroform protocols or silica‑based column kits. These techniques lyse cells, disrupt ribonucleoprotein complexes, and precipitate RNA while removing DNA, proteins, and other contaminants. The purity of the isolated RNA is assessed by spectrophotometric ratios (A260/280 ≈ 2.0) and integrity is evaluated using capillary electrophoresis, yielding an RNA integrity number (RIN) value.

Applications of totalRNA include global RNA‑sequencing (RNA‑seq) workflows, small RNA profiling, ribosome profiling, and quantitative PCR assays that target multiple RNA species. Because totalRNA contains rRNA, careful library preparation strategies such as rRNA–depletion are employed to focus sequencing reads on the transcripts of interest. In clinical diagnostics, totalRNA is used to detect viral RNAs, biomarkers, and gene expression signatures in tissues, blood, or other fluids. Researchers often choose totalRNA extraction when they require an unbiased view of the transcriptome, especially in exploratory studies where the roles of non‑coding RNAs are unknown.