UniProtKB consists of two sections, UniProtKB/Swiss-Prot and UniProtKB/TrEMBL. The former contains manually annotated records with information extracted from literature and curator-evaluated computational analysis. Annotation is done by biologists with specific expertise to achieve accuracy. In UniProtKB/Swiss-Prot, annotation consists of the description of the following: function(s), enzyme-specific information, biologically relevant domains and sites, post-translational modifications, subcellular location(s), tissue specificity, developmental specific expression, structure, interactions, splice isoform(s), associated diseases or deficiencies or abnormalities, etc. Another important part of the annotation process involves merging of different reports for a single protein. After an inspection of the sequences, the curator selects the reference sequence, does the corresponding merging, and lists the splice and genetic variants along with disease information when available. UniProtKB/TrEMBL contains high quality computationally analyzed records enriched with automatic annotation and classification. The computer-assisted annotation is created using automatically generated rules as in Spearmint (2) or manually curated rules (UniRule) (3–6) based on protein families. UniProtKB/TrEMBL contains the translations of all coding sequences (CDS) present in the EMBL/GenBank/DDBJ Nucleotide Sequence Databases (7) and sequences from TAIR Arabidopsis thaliana (8), SGD (9) and
