RNA tomography is an innovative technique used to map gene expression patterns in three dimensions (3D). Imagine trying to get a detailed picture of how genes are active within the cells of a tissue sample, not just from a flat 2D view, but from all angles—this is what RNA tomography aims to do. It provides a clearer understanding of how genes function spatially, which is important because genes don’t work in isolation—they interact with each other in specific locations within cells and tissues.

What is Tomo-seq and How Does RNA Tomography Work?

Researchers at the University of Tsukuba have developed Tomo-seq (short for RNA sequencing of cryosection samples), a method used to collect data about gene expression across different layers of a tissue sample. The tissue is sliced into thin sections, which are then analyzed using RNA sequencing (RNA-seq) to see which genes are active in each section. These slices are taken along three different axes of the tissue, providing a 3D perspective of the tissue’s gene activity.

However, interpreting this 1D data (from individual tissue slices) to get a complete 3D picture can be quite complex. This is where RNA tomography comes in. It uses computational methods to reconstruct the 3D gene expression patterns from the individual slices, giving researchers a more comprehensive view of how genes behave in their natural spatial context.

Overview of tomoseqr

Based on 1D tomo-seq data along three mutually orthogonal axes and a mask data, tomoseqr performs RNA tomography using iterative proportional fitting and reconstructs a 3D expression pattern of each gene. A GUI called masker helps users to design and edit a mask data. Another GUI Image viewer visualizes the reconstructed gene expression patterns in 2D or 3D view.

The tomoseqr R Package: Making RNA Tomography Accessible

To make this process easier for researchers, a new tool called tomoseqr has been developed. This is an R package, meaning it’s a software tool built to work with the R programming language, commonly used in biology and data analysis. Tomoseqr allows scientists to analyze tomo-seq data, reconstruct the 3D patterns of gene expression, and visualize the results using easy-to-use graphical interfaces.

What’s great about tomoseqr is that it’s designed to be user-friendly, even for researchers who might not have extensive experience with computational biology. The package takes the raw data from tomo-seq, processes it, and helps researchers see how gene expression is distributed across the 3D tissue sample. This can provide important insights into how genes are regulated in specific regions of a tissue, or how their activity changes in different conditions or diseases.

Testing the Effectiveness of tomoseqr

In the development of tomoseqr, the researchers tested its functionality with both simulated data (generated for testing purposes) and real-world data from actual biological samples. These tests demonstrated that tomoseqr is effective at reconstructing accurate 3D gene expression patterns, confirming that it’s a valuable tool for researchers in the field.

By using tomoseqr, scientists can more easily analyze and interpret complex gene expression data from tissue samples, helping them understand the spatial organization of gene activity. This can lead to new discoveries in areas like tissue development, disease progression, and even personalized medicine.

Conclusion

RNA tomography is an exciting advancement in the way we study gene expression, offering a 3D view of how genes interact within their biological context. The tomoseqr R package makes this powerful technique more accessible to researchers, enabling them to analyze and visualize 3D gene expression patterns with ease. Whether you’re a biologist, bioinformatician, or researcher in related fields, tomoseqr could be the tool you need to gain deeper insights into the spatial dynamics of gene activity in tissues.

Availability – R package tomoseqr is available on Bioconductor (https://doi.org/doi:10.18129/B9.bioc.tomoseqr) and GitHub (https://github.com/bioinfo-tsukuba/tomoseqr).