Annotation and analysis of low-complexity protein families of Anopheles gambiae that are associated with cuticle

We have characterized four new families of homologous genes of the mosquito, Anopheles gambiae, all of which include members shown by previous work to be cuticular in nature. The CPLCG, CPLCW, CPLCP, and CPLCA families (where CPLC is 'cuticular protein of low complexity') encode proteins with a high proportion of low-complexity sequence. We have also annotated the An. gambiae Tweedle genes, a family of cuticular protein genes first described in Drosophila, and additional ungrouped An. gambiae cuticular proteins identified by proteomics. Our annotations reveal multiple gene-family expansions that are specific to Diptera or Culicidae. The CPLCG and CPLCW families occur within a large and dynamic tandem array on chromosome 3R that includes sets of concertedly evolving genes. Most gene families exhibit two or more different expression profiles during development.