Download Tracking a putative novel category copper type 3 protein across

Tracking a putative novel category copper type 3 protein across evolution of snails
(Hygrophila) by comparative genomics.
Janeth J. Peña and Coen M. Adema
Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New
Mexico.
Background and Objective
The schistosome parasite-transmitting snail Biomphalaria glabrata (family Planorbidae),
expresses a hemocyanin-like protein (Hcl-1) highly similar to, yet different from respiratory
hemocyanins of arthropods and molluscs, belonging to the copper type 3 protein superfamily.
The presence of Hcl-1 is unexpected; secondarily evolved hemoglobin has replaced
hemocyanin for oxygen transport in planorbid snails. Toward functional characterization, we
sequenced the B. glabrata Hcl-1 gene and screened for Hcl-1 in Planorbidae and sister taxa of
hygrophilid snails, Physidae and Lymnaeidae that possess only hemocyanin.
Methods
NGS, Gene characterization, Annotation, Bioinformatics, SDS-PAGE, immunoblotting.
Results
Hcl-1 is a novel copper type 3 protein, different from prophenoloxidase, tyrosinase and
hemocyanin. Hcl-1 is present in Planorbid snails and their egg masses but may be absent from
the sister-taxa Physidae and Lymnaeidae.
Discussion and Conclusions
Hcl-1 may derive from hemocyanin through gene repurposing after advent of hemoglobin as
new respiratory pigment in planorbid snails. Most similar to hemocyanin, we propose that Hcl-1
represents a novel copper type 3 protein that is deposited in egg masses, possibly in support of
snail reproduction.
This study was supported by NIH grant P30GM110907. JJP recognizes the Latin American and
Iberian Institute (LAII) at UNM for stipend and the Alvin R. and Caroline Grove scholarship from
the Department of biology, UNM.