The proteome survey of an electricity-generating organ (Torpedo californica electric organ).
Torpedo californica is a species in class Chondrichthyes. Electric rays have evolved the electric organ, which is similar to the mammalian neuromuscular junction (NMJ). Here, we took a combined cDNA sequencing and proteomic approach to define the molecular constituents of the T. californica electric organ. For soluble proteins, 2-DE was used and 224 protein spots were mapped. Plasma membrane fractions were analyzed using the shotgun approach (LC-MS/MS). A Torpedo cDNA library was constructed and 607 cDNA clones were sequenced. Identification of electric organ proteins was done using cross-species comparisons, and a custom database was constructed from cDNA translations. We unambiguously identified 121 proteins and transcripts, 103 of which were novel additions to the existing databases of Torpedo fish. Fifteen proteins of known function, but not previously associated with either the electroplaque or NMJ, were present at high abundance. These included the heat shock and oxidative stress proteins, annexin V (calelectrin), and plectin 1. Most interesting were the unambiguous matches to 11 human ORFs of unknown function, including four potential RNA splicing proteins, a vacuolar sorting protein, and a tetraspanin containing protein. This analysis identified proteins that may play a role in the higher vertebrate neuromuscular junction or other electrical synapses.
Nazarian
Javad
J
Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA.
Hathout
Yetrib
Y
Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA.
Vertes
Akos
A
Department of Chemistry, George Washington University, Washington, DC, USA.
Hoffman
Eric P
EP
Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA.
D000595:Amino Acid Sequence; D000818:Animals; D018076:DNA, Complementary / Q000378:metabolism; D004557:Electric Organ / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D015723:Gene Library; D008969:Molecular Sequence Data; D010802:Phylogeny; D020543:Proteome / Q000378:metabolism*; D014101:Torpedo / Q000378:metabolism*
D018076:DNA, Complementary; D020543:Proteome