Expression
ZSG determines DNA molecule quantity by directly counting the molecules in a sample.
cDNA molecules are individually visible. There is no amplification, no need for fluorescent “interpretation.” Single-cell, single-molecule transcript analysis with splicing sensitivity should be especially useful for understanding cancer, immune, developing and nerve cells.
 |
cDNA molecules directly visible. (The circle defines the binding region). |
Background
In order to translate information stored in DNA into action, a cell makes a copy (RNA) of the short, relevant portion of the DNA. These RNA molecules are then cut apart and reassembled into any of several flavors (splice variants), each with unique function.
In any given cell, 10-30% of the genes are “expressed,” or actively giving instructions to the cell about making proteins (the cell’s “worker” molecules). When the cell changes its shape or behavior, or when it becomes infected, the amount of RNA produced by some genes goes up or down to various degrees. Gene Expression tools measure the expression of genes by measuring levels of RNA.
Expression Application
The ZS Genetics Expression System is targeted for 2008.
Our Gene Expression system images samples on a proprietary ZSG microarray using an electron microscope. cDNA’s are individually visible and are counted directly. Partial sequence information is also available along the length of the molecule, providing splice pattern data. This highly sensitive system will be optimized for samples of 1 to 50 cells and is especially valuable for single-cell analysis. No amplification or use of florescence is required. Our Reaction Kits include single-use microarrays and the reagents needed to prepare samples for reading.
The Reading System
- Specially-modified transmission electron microscope manufactured by the world’s leader in electron microscopes.
- Digital imaging system to capture and process the Expression data.
- Control and analysis software to operating system, analyze images, assess accuracy and export data.
- Modular architecture for upgrades. System sensitivity and throughput are driven by the software and the digital camera. These are both modular, allowing users low-cost upgrade path to keep pace with advancing technologies.
Reaction Kit
- Nano-scale oligo-array, standard or custom, with 50 base oligos
- All reagents needed for labeling a purified sample and hybridizing it to the microarray.
- Kits expected to cost dramatically less than other commercial expression consumables
Familiar methods, unique results.
Like most microarrays, defined areas of the surface (features) will have oligonucleotide probes (50 bases long for ZSG) designed to hybridize with specific sequences of cDNA targets. The location of the feature therefore identifies the transcript. Our arrays will have a low probe density, to separate individual hybridized molecules for more precise counting. The probes themselves remain transparent (low Z), but contribute to image interpretation by forcing the cDNA with opaque labels into a local helix, which appears as a series of dark dots where a nucleotide includes a labeling atom. Low density probe organization also promotes faster and more reliable hybridization. ZSG measures Expression by direct counting of molecules within each feature therefore providing maximum sensitivity. ZSG will offer standard microarrays and custom ones designed by the user.
Please contact us at inquiries@zsgenetics.com to learn more about our Expression System and trial program.
Advantages
Detecting and understanding early stages of diseases, especially cancer, has great potential for finding effective treatments. Our technology works naturally at the scale of life, a single cell.
Single Cells
We can offer the Gene Expression performance of single-molecule sensitivity on samples of a single cell. We believe our technology will be more precise than quantitative PCR, and able to assess thousands of genes in a single assay. While less massively parallel than florescent microarray technologies, it will be far more precise, sensitive and reproducible.
Expression analysis on a single cell avoids the loss of data when multiple cells are combined into one sample. A range of transcript abundance is expected across cells for any gene, but averaging the expression into a single measurement masks the differences. Or, if a sample has only a few diseased cells, their abnormal expression may not move the average enough to be detected.
These characteristics are why we see one natural use for our technology as the precise identification and understanding of moderately-complex to highly-complex pathways that critically include low abundance transcripts or splice variants. Our technology will be uniquely, and cheaply, capable of evaluating subtle mechanisms, especially control systems that take place on the level of individual cells.
Please e-mail inquiries@zsgenetics.com for more information.