Macroarray analysis of coelomocyte gene expression in response to LPS in the sea urchin. Identification of unexpected immune diversity in an invertebrate.
The purple sea urchin, Strongylocentrotus purpuratus, is a member of the phylum Echinodermata, which is basal to the phylum Chordata within the deuterostome lineage of the animal kingdom. This relationship makes the analysis of the sea urchin immune system relevant to understanding the evolution of the deuterostome immune system leading to the Vertebrata. Subtractive suppression hybridization was employed to generate cDNA probes for screening high-density arrayed, conventional cDNA libraries to identify genes that were upregulated in coelomocytes responding to lipopolysaccharide. Results from 1,247 expressed sequence tags (ESTs) were used to infer that coelomocytes upregulated genes involved in RNA splicing, protein processing and targeting, secretion, endosomal activities, cell signaling, and alterations to the cytoskeletal architecture including interactions with the extracellular matrix. Of particular note was a set of transcripts represented by 60% of the ESTs analyzed, which encoded a previously uncharacterized family of closely related proteins, provisionally designated as 185/333. These transcripts exhibited a significant level of variation in their nucleotide sequence and evidence of putative alternative splicing that could yield up to 15 translatable elements. On the basis of the striking increase in gene expression in response to lipopolysaccharide and the unexpected level of diversity of the 185/333 messages, we propose that this set of transcripts encodes a family of putative immune response proteins that may represent a major component of an immunological response to bacterial challenge.
Nair
Sham V
SV
Department of Biological Sciences, George Washington University, Washington, District of Columbia 20052, USA.
Del Valle
Heather
H
Gross
Paul S
PS
Terwilliger
David P
DP
Smith
L Courtney
LC
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation; D003599:Cytoskeleton / Q000378:metabolism; D018076:DNA, Complementary; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D007113:Immunity, Innate / Q000187:drug effects* / Q000235:genetics*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis / Q000235:genetics; D011499:Protein Processing, Post-Translational / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012617:Sea Urchins / Q000187:drug effects* / Q000235:genetics* / Q000276:immunology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D008070:Lipopolysaccharides