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Duncan Brown

Publications and source records attributed to Duncan Brown.

3 recordsLinked to original sources

Subfamily hmms in functional genomics.

The limitations of homology-based methods for prediction of protein molecular function are well known; differences in domain structure, gene duplication events and errors in existing database annotations complicate this process. In this paper we present a method to detect and model protein subfamilies, which can be used in high-throughput, genome-scale phylogenomic inference of protein function. We demonstrate the method on a set of nine PFAM families, and show that subfamily HMMs provide greater separation of homologs and non-homologs than is possible with a single HMM for each family. We also show that subfamily HMMs can be used for functional classification with a very low expected error rate. The BETE method for identifying functional subfamilies is illustrated on a set of serotonin receptors.

Animals↗

Arabidopsis downy mildew resistance gene RPP27 encodes a receptor-like protein similar to CLAVATA2 and tomato Cf-9.

The Arabidopsis Ler-RPP27 gene confers AtSgt1b-independent resistance to downy mildew (Peronospora parasitica) isolate Hiks1. The RPP27 locus was mapped to a four-bacterial artificial chromosome interval on chromosome 1 from genetic analysis of a cross between the enhanced susceptibility mutant Col-edm1 (Col-sgt1) and Landsberg erecta (Ler-0). A Cf-like candidate gene in this interval was PCR amplified from Ler-0 and transformed into mutant Col-rpp7.1 plants. Homozygous transgenic lines conferred resistance to Hiks1 and at least four Ler-0 avirulent/Columbia-0 (Col-0) virulent isolates of downy mildew pathogen. A full-length RPP27 cDNA was isolated, and analysis of the deduced amino acid sequences showed that the gene encodes a receptor-like protein (RLP) with a distinct domain structure, composed of a signal peptide followed by extracellular Leu-rich repeats, a membrane spanning region, and a short cytoplasmic carboxyl domain. RPP27 is the first RLP-encoding gene to be implicated in disease resistance in Arabidopsis, enabling the deployment of Arabidopsis techniques to investigate the mechanisms of RLP function. Homology searches of the Arabidopsis genome, using the RPP27, Cf-9, and Cf-2 protein sequences as a starting point, identify 59 RLPs, including the already known CLAVATA2 and TOO MANY MOUTHS genes. A combination of sequence and phylogenetic analysis of these predicted RLPs reveals conserved structural features of the family.

Amino Acid Sequence↗