Four differentially expressed cDNAs containing the Rebers-Riddiford consensus sequence in Callinectes sapidus

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Anna Wynn (Creator)
The University of North Carolina Wilmington (UNCW )
Web Site:
Thomas Shafer

Abstract: Decapod crustaceans such as Callinectes sapidus, the blue crab, provide a unique opportunity to study proteins involved in biomineralization. Subsequent to each molt, the majority of the exoskeleton (e.g. dorsal carapace) calcifies while morphologically similar cuticle at the joints (arthrodial membrane) remains uncalcified. Several proteins from both types of cuticle contain the chitin-binding Rebers-Riddiford (RR) consensus sequence, Gx8Gx7YxAxExGYx7Px2P. This study obtained sequence and expression data for four transcripts containing the RR consensus sequence from hypodermal tissue of C. sapidus. Expression analyses using Northern blots and quantitative PCR revealed that two of the transcripts, CsAMP8.1 and CsAMP6.0, are found only in arthrodial membrane and expressed uniformly both before and after the molt. Analyses of the remaining two transcripts, CsCP8.5 and CsCP8.2, revealed that both are expressed solely in pre-molt carapace, indicating possible involvement in the postmolt mineralization of the pre-exuvial cuticle. NCBI BLAST results for CsAMP8.1 and CsAMP6.0 identified sequence homology with proteins containing the RR consensus sequence found in the uncalcified membranes of Cancer pagarus, Penaeus japonicus, and Homarus americanus. NCBI BLAST results for CSCP8.5 and CSCP8.2 identified sequence homology with calcification-associated peptides containing the RR consensus sequence obtained from the calcified cuticle of Procambarus clarkii. These results add C. sapidus to the list of arthropods containing cuticular proteins with the characteristic RR consensus sequence. The differential expression of these four genes is consistent with the hypothesis that RR-containing proteins play an important role in regulating calcification.

Additional Information

A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment Of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Biomineralization, Blue crab--Morphology, Blue crab--Physiology, Blue crab--Research, Carrier proteins
Blue crab -- Morphology
Blue crab -- Physiology
Blue crab -- Research
Carrier proteins

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