title: Transcription profiling reveals stage- and function-dependent expression patterns in the filarial nematode Brugia malayi.
abstract: BACKGROUND
  Brugia malayi is a nematode parasite that causes lymphatic filariasis, a disfiguring and disabiling tropical disease. Although a first draft genome sequence was released in 2007, very little is understood about transcription programs that govern developmental changes required for the parasite's development and survival in its mammalian and insect hosts.
  
  
  RESULTS
  We used a microarray with probes that represent some 85% of predicted genes to generate gene expression profiles for seven parasite life cycle stages/sexes. Approximately 41% of transcripts with detectable expression signals were differentially expressed across lifecycle stages. Twenty-six percent of transcripts were exclusively expressed in a single parasite stage, and 27% were expressed in all stages studied. K-means clustering of differentially expressed transcripts revealed five major transcription patterns that were associated with parasite lifecycle stages or gender. Examination of known stage-associated transcripts validated these data sets and suggested that newly identified stage or gender-associated transcripts may exercise biological functions in development and reproduction. The results also indicate that genes with similar transcription patterns were often involved in similar functions or cellular processes. For example, nuclear receptor family gene transcripts were upregulated in gene expression pattern four (female-enriched) while protein kinase gene family transcripts were upregulated in expression pattern five (male-enriched). We also used pair-wise comparisons to identify transcriptional changes between life cycle stages and sexes.
  
  
  CONCLUSIONS
  Analysis of gene expression patterns of lifecycle in B. malayi has provided novel insights into the biology of filarial parasites. Proteins encoded by stage-associated and/or stage-specific transcripts are likely to be critically important for key parasite functions such as establishment and maintenance of infection, development, reproduction, and survival in the host. Some of these may be useful targets for vaccines or new drug treatments for filariasis.
authors.affiliation: Infectious Diseases Division, Department of Internal Medicine, Washington University School of Medicine, St, Louis, MO 63110, USA. bli@wustl.edu
authors.forename: Ben-Wen
authors.initials: BW
authors.lastname: Li
authors.forename: Zhengyuan
authors.initials: Z
authors.lastname: Wang
authors.forename: Amy C
authors.initials: AC
authors.lastname: Rush
authors.forename: Makedonka
authors.initials: M
authors.lastname: Mitreva
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Weil
mesh_terms: D000818:Animals; D017178:Brugia malayi / Q000235:genetics* / Q000254:growth & development; D016000:Cluster Analysis; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D008018:Life Cycle Stages / Q000235:genetics; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D009866:Oogenesis / Q000235:genetics; D018510:RNA, Helminth / Q000378:metabolism; D013091:Spermatogenesis / Q000235:genetics; D015854:Up-Regulation
chemical_list: D018510:RNA, Helminth