Related Experiment Videos
J chain in the nurse shark: implications for function in a lower vertebrate
Valerie S Hohman1, Sue E Stewart, Lynn L Rumfelt
1Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|June 10, 2003
Summary
The J chain in nurse sharks differs significantly from mammalian J chains, lacking key features for immunoglobulin secretion. This suggests J chain may not be involved in Ig secretion in this species.
Area of Science:
- Immunology
- Evolutionary Biology
- Marine Biology
Background:
- J chain is crucial for polymeric immunoglobulin (Ig)A and IgM transport in mammals.
- Its function in non-mammalian vertebrates is largely unknown.
Purpose of the Study:
- To identify and characterize the J chain in nurse sharks.
- To investigate the potential role of nurse shark J chain in immunoglobulin secretion.
Main Methods:
- Sequence analysis of nurse shark cDNA.
- Polypeptide isolation from nurse shark IgM.
- Comparative sequence analysis with J chains from other species.
Main Results:
- Nurse shark J chain exhibits poor conservation, particularly in the carboxyl-terminal region.
- It lacks acidic properties and three conserved half-cystine residues found in mammalian J chains.
- J chain transcripts are abundant in spleen but absent in the intestine.
Conclusions:
- Nurse shark J chain possesses unique characteristics that may preclude its role in Ig secretion.
- Phylogenetic analysis of J chain sequences supports accepted evolutionary relationships, questioning invertebrate J chain presence.