The German cDNA Consortium

S. Wiemann, H. Blöcker, K. Köhrer, A. Hörlein, J. Lauber, B. Ottenwälder, R. Wambutt, A. Poustka

The German cDNA Consortium generates sequence verified clone resources for functional exploitation in downstream high-throughput experiments. This consortium was founded in 1996 to systematically clone and analyze novel human genes by means of cDNA library production, EST Sequencing, and subsequent full-insert sequencing of candidate full-length cDNAs (Wiemann et al., 2001). The novelty rate in EST sequencing has significantly dropped since, requiring alternative routes to be developed in order to clone the remaining ~40% of the human genes.

Hence, the German cDNA Consortium has devised strategies to directly clone the protein coding regions of protein-coding genes, and to thus substantially contribute to a world-wide effort towards completion of the human gene set, both as sequence and as physical clones (Bechtel et al., 2007). The ORF-cloning process consists of four consecutive processes.

• Modeling of gene structures - manual annotation of genes and gene structures is required to finish the catalog of human genes (in silico).

• Cloning of ORFs - genes and splice variants - Expression clones make the encoded proteins amenable to their functional analysis.

• Sequence validation of gene models and ORF sequences - Quality control of the clone resource is the basis for its experimental exploitation, and validates gene models.

• Processing of entry clones to generate expression-ready clones for recombinant protein expression in heterologous systems (e.g. mammalian, yeast, bacterial) follows sequence validation.
  All steps in the cloning and verification process require a tight management of laboratory information. This is provided by the infostructure project, providing software and databases that are utilized at the cloning and sequencing centers.

The clones and sequences are made available for experimental exploitation via the International ORFeome Collaboration and the EMBL/GenBank/DDBJ databases, respectively.