Massive parallel signature sequencing (MPSS) is a procedure that is used to identify and quantify mRNA transcripts, resulting in data similar to serial analysis of gene expression (SAGE), although it employs a series of biochemical and sequencing steps that are substantially different.
How it works
MPSS is a method for determining expression levels of mRNA by counting the number of individual mRNA molecules produced by each gene. It is "open ended" in the sense that the identity of the RNAs to be measured are not pre-determined as they are with gene expression microarrays.
A sample of mRNA are first converted to complementary DNA (cDNA) using reverse transcriptase, which makes subsequent manipulations easier. These cDNA are fused to a small oligonucleotide "tag" which allows the cDNA to be PCR amplified and then coupled to microbeads. After several rounds of sequence determination, using hybridization of fluorescent labeled probes, a sequence signature of ~16–20 bp is dete