The Pronto!™ Plus System from Promega and Corning offers microarray facilities the first end-to-end solution for microarray users. The system includes a complete set of reagents that provides a fully optimized protocol from printing to hybridization of DNA microarrays. This product is the first to emerge from the business alliance between Corning and Promega, which was announced in October 2003. The two companies collaborated to develop this complete system to control variability throughout the entire microarray process, including printing, RNA isolation, direct labeling, and array hybridization.
The Pronto!™ Plus System includes UltraGAPS™ Slides and the necessary reagents for printing, hybridizing and washing long oligonucleotide and cDNA microarrays. The SV Total RNA isolation system provides a fast and simple technique for preparing total RNA, from a variety of sources, in one hour. The ChipShot™ Labelling and Clean-Up systems generates fluorescent cDNAs by direct labelling using CyDye-coupled dNTPs. The labelling system has been optimised for 5ug of total RNA per labelling reaction (or 1.5ug of Poly(A)+RNA).
There are currently six configurations of the Pronto!™ Plus system, each tailored to match specific researcher needs. The first two systems are intended for core facilities to validate Pronto reagents from microarray manufacture through to hybridization. Another two systems are designed to purify total RNA, generate labelled cDNA and hybridize to microarrays printed on UltraGAPS™ slides. The final two systems are configured for researchers who already have purified total RNA but need to label cDNA prior to hybridization to microarrays printed on UltraGAPS™ slides.
The Pronto!™ Plus systems can look attractive for inexperienced researchers as it may reduce workload as all reagent preparation, validation and optimization is already completed. Alternatively, this system could be recommended by microarray production facilities to inexperienced collaborators. It has been shown that through standardized production methods and stringent QC control, interslide variation of less than 10% is achieved.
I have been evaluating this kit for the last three months. I tried not to deviate from the protocol, as our intention is to recommend this kit to inexperienced external collaborators (we produce oligonucleotide microarrays). A typical labelling reaction will yield enough material to hybridize 2 to 4 slides, starting from 5 ug of total RNA. The reproducibility tests that I did were good. The main source of variability came from the hybridization step using conventional slide coverslips.
In its current configuration, the system is fully integrated, which means that it is not compatible with alternative labelling methods (e.g. indirect labelling) or with an automated hybridization system (e.g. Ventana Discovery platform). As it is not possible to order the different kit components separately, it may be difficult to incorporate this system in an existing microarray core facility.
In summary, I do recommend this kit for researchers who are looking for a fully validated protocol from microarray printing to hybridization. There are no specific inovations in these kits. What you pay for is a validated end-to-end system, which is still currently a big challenge encountered by most researchers setting-up microarray core facilities. Concerning cost, this system is still expensive, but prices are likely to go down in the near future.
Jean-Baptiste Rascle, Ph.D.
Principal Investigator
Institut de Pharmacologie Moléculaire et Cellulaire
CNRS
France