This invention provides methods of monitoring the expression levels of a multiplicity of genes. The methods involve hybridizing a nucleic acid sample to a high density array of oligonucleotide probes where the high density array contains oligonucleotide probes complementary to subsequences of target nucleic acids in the nucleic acid sample. In one embodiment, the method involves providing a pool of target nucleic acids comprising RNA transcripts of one or more target genes, or nucleic acids derived from the RNA transcripts, hybridizing said pool of nucleic acids to an array of oligonucleotide probes immobilized on surface, where the array comprising more than 100 different oligonucleotides and each different oligonucleotide is localized in a predetermined region of the surface, the density of the different oligonucleotides is greater than about 60 different oligonucleotides per 1 cm2, and the oligonucleotide probes are complementary to the RNA transcripts or nucleic acids derived from the RNA transcripts; and quantifying the hybridized nucleic acids in the array.

Expression monitoring by hybridization to high density oligonucleotide arrays

Rapid improvements in sequencing and array-based platforms are resulting in a flood of diverse genome-wide data, including data from exome and whole-genome sequencing, epigenetic surveys, expression profiling of coding and noncoding RNAs, single nucleotide polymorphism (SNP) and copy number profiling, and functional assays. Analysis of these large, diverse data sets holds the promise of a more comprehensive understanding of the genome and its relation to human disease. Experienced and knowledgeable human review is an essential component of this process, complementing computational approaches. This calls for efficient and intuitive visualization tools able to scale to very large data sets and to flexibly integrate multiple data types, including clinical data. However, the sheer volume and scope of data pose a significant challenge to the development of such tools.

Integrative Genomics Viewer

The real-time reverse transcription polymerase chain reaction (RT-qPCR) addresses the evident requirement for quantitative data analysis in molecular medicine, biotechnology, microbiology and diagnostics and has become the method of choice for the quantification of mRNA. Although it is often described as a "gold" standard, it is far from being a standard assay. The significant problems caused by variability of RNA templates, assay designs and protocols, as well as inappropriate data normalization and inconsistent data analysis, are widely known but also widely disregarded. As a first step towards standardization, we describe a series of RT-qPCR protocols that illustrate the essential technical steps required to generate quantitative data that are reliable and reproducible. We would like to emphasize, however, that RT-qPCR data constitute only a snapshot of information regarding the quantity of a given transcript in a cell or tissue. Any assessment of the biological consequences of variable mRNA levels must include additional information regarding regulatory RNAs, protein levels and protein activity. The entire protocol described here, encompassing all stages from initial assay design to reliable qPCR data analysis, requires approximately 15 h.

Quantification of mRNA using real-time RT-PCR

The polymerase chain reaction (PCR) is increasingly used as the standard method for detection and characterization of microorganisms and genetic markers in a variety of sample types. However, the method is prone to inhibiting substances, which may be present in the analysed sample and which may affect the sensitivity of the assay or even lead to false-negative results. The PCR inhibitors represent a diverse group of substances with different properties and mechanisms of action. Some of them are predominantly found in specific types of samples thus necessitating matrix-specific protocols for preparation of nucleic acids before PCR. A variety of protocols have been developed to remove the PCR inhibitors. This review focuses on the general properties of PCR inhibitors and their occurrence in specific matrices. Strategies for their removal from the sample and for quality control by assessing their influence on the individual PCR test are presented and discussed.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.2012.05384.x

PCR inhibitors - occurrence, properties and removal.

http://hemepathreview.com/UsefulHemeRefArticles/Monitor-CML-Standards.pdf

Monitoring CML patients responding to treatment with tyrosine kinase inhibitors: review and recommendations for harmonizing current methodology for detecting BCR-ABL transcripts and kinase domain mutations and for expressing results

The widespread use of sensitive assays for the detection of viral and cellular RNA sequences has created a need for stable, well-characterized controls and standards. We describe the development of a versatile, novel system for creating RNase-resistant RNA. “Armored RNA” is a complex of MS2 bacteriophage coat protein and RNA produced in Escherichia coli by the induction of an expression plasmid that encodes the coat protein and an RNA standard sequence. The RNA sequences are completely protected from RNase digestion within the bacteriophage-like complexes. As a prototype, a 172-base consensus sequence from a portion of the human immunodeficiency virus type 1 (HIV-1) gag gene was synthesized and cloned into the packaging vector used to produce the bacteriophage-like particles. After production and purification, the resulting HIV-1 Armored RNA particles were shown to be resistant to degradation in human plasma and produced reproducible results in the Amplicor HIV-1 Monitor assay for 180 days when stored at −20°C or for 60 days at 4°C. Additionally, Armored RNA preparations are homogeneous and noninfectious.

Armored RNA Technology for Production of Ribonuclease-Resistant Viral RNA Controls and Standards

The present invention is directed to the process of creating a recombinant nucleic acid standard which is resistant to ribonuclease digestion and is non-infectious. A single strand of recombinant nucleic acid is encapsidated by bacteriophage proteins. The recombinant nucleic acid is a hybrid sequence encoding bacteriophage proteins and a specific non-bacteriophage sequence. A non-bacteriophage RNA sequence can be used as an RNA standard to help quantify the number of RNA molecules in an unknown sample. The recombinant RNA in its packaged form is highly resistant to ribonucleases, insuring that the RNA standard is not compromised by inadvertent ribonuclease contamination. These "ARMORED RNA" standards are ideal as RNA standards for the quantification of RNA viruses such as HIV and HCV from human body fluids such as blood and cerebrospinal fluid.

Ribonuclease resistant viral RNA standards

Disclosed are methods that allow one or more nucleic acid targets to be compared across two or more nucleic acid samples. Nucleic acid tags are appended to the samples to be assessed, such that each sample has a unique tag. The tagged nucleic acids are then mixed, and the targets within the mixture are amplified. The amplification products are distinguished using the unique tag domains to reveal the abundance of the amplification products derived from each sample, which correlates to the relative abundance of the target in the samples.

Comparative analysis of nucleic acids using population tagging

Methods and compositions for inhibiting and/or inactivating nucleases by employing nuclease inhibitors are provided. The nuclease inhibitors comprise anti-nuclease antibodies and non-antibody nuclease inhibitors. The anti-nuclease antibodies of the present invention may be a polyclonal or monoclonal antibodies, and may be anti-ribonuclease antibodies, anti-deoxyribonuclease antibodies, or antibodies to non-specific nucleases. A preferred embodiment comprises at least two nuclease inhibitors, and is referred to as a nuclease inhibitor cocktail. In some specific embodiments, the invention concerns methods of performing in vitro translation comprising obtaining a first nuclease inhibitor, which inhibitor is further defined as an anti-nuclease antibody, and placing the anti-nuclease antibody in an in vitro translation reaction. In many cases, the in vitro translation reaction comprises at least one nuclease, which may be a ribonuclease, a deoxyribonuclease, or a nonspecific nuclease. The invention also relates to kits for the performance of various microbiological procedures, which kits comprise the nuclease inhibitors described herein.

Nuclease inhibitor cocktail

Background: Comparison and evaluation of molecular diagnostic assays for the detection and quantification of hepatitis C virus (HCV) RNA have been limited by the lack of RNA controls and calibrators. Armored RNA ® technology is a means for producing RNA that is completely protected from plasma ribonucleases. This method produces recombinant pseudoviral particles that are noninfectious and contain predefined RNA sequences. Methods: A consensus 412-base sequence from the 5′NCR/Core region of HCV subtype 2b was derived from 34 individually sequenced HCV genotype 2b variants. A DNA fragment encoding the consensus HCV-2b sequence was synthesized de novo, cloned, and expressed as an Armored RNA control. The resulting HCV-2b Armored RNA (AR-HCV-2b) contained the complete HCV-2b consensus RNA sequence encapsidated within a protective protein coat. Results: AR-HCV-2b was fully recoverable from human plasma incubated at 4 °C for >300 days. The particles were tested in three clinical assay formats: Amplicor TM HCV Monitor 1.0, Quantiplex TM HCV RNA 2.0, and INNO-LiPA TM HCV II. When added into seronegative, nonviremic plasma, AR-HCV-2b showed reproducible signals and linear dilutions in both the Amplicor and Quantiplex assays. AR-HCV-2b was correctly identified as subtype 2b in the INNO-LiPA line probe assay. Conclusion: The HCV-2b Armored RNA control is a versatile, durable, ribonuclease-resistant viral RNA control that is compatible in three different clinical assay formats.

Matthew M. Winkler

Papers

Armored RNA Technology for Production of Ribonuclease-Resistant Viral RNA Controls and Standards

Ribonuclease resistant viral RNA standards

Comparative analysis of nucleic acids using population tagging

Nuclease inhibitor cocktail

Ribonuclease-resistant RNA Controls (Armored RNA) for Reverse Transcription-PCR, Branched DNA, and Genotyping Assays for Hepatitis C Virus