Project description:The mantle is a thin tissue from which proteins are secreted dictating the mollusk shell construction. As a conserved organ involved in shell formation throughout mollusks, the mantle is an excellent foundation from which to study biomineralization. A P. maxima mantle tissue specific cDNA microarray, termed PmaxArray 1.0, has been developed comprising 5000 cDNA transcripts derived from the mantle tissue of P. maxima. This tool has been used to investigate the spatial functional dynamics of the mantle tissue identifying over 2000 PmaxArray 1.0 spots as differentially expressed spatially within this organ. Gene expression profiles observed for these transcripts indicated 5 major spatial functions for the mantle, 3 of which have been putatively attributed to shell formation roles associated with nacre microstructure, calcite prismatic microstructure and periostracum. These transcripts are further examined with in situ expression localization and comparative sequence analyses in reference to potential shell formation roles. This spatial investigation has expedited the elucidation of functions within the dynamic mantle organ, paying particular attention to of shell biomineralization. Keywords: Spatial expression profiling by array
Project description:The mantle is a thin tissue from which proteins are secreted dictating the mollusk shell construction. As a conserved organ involved in shell formation throughout mollusks, the mantle is an excellent foundation from which to study biomineralization. A P. maxima mantle tissue specific cDNA microarray, termed PmaxArray 1.0, has been developed comprising 5000 cDNA transcripts derived from the mantle tissue of P. maxima. This tool has been used to investigate the spatial functional dynamics of the mantle tissue identifying over 2000 PmaxArray 1.0 spots as differentially expressed spatially within this organ. Gene expression profiles observed for these transcripts indicated 5 major spatial functions for the mantle, 3 of which have been putatively attributed to shell formation roles associated with nacre microstructure, calcite prismatic microstructure and periostracum. These transcripts are further examined with in situ expression localization and comparative sequence analyses in reference to potential shell formation roles. This spatial investigation has expedited the elucidation of functions within the dynamic mantle organ, paying particular attention to of shell biomineralization. Keywords: Spatial expression profiling by array The mantle tissue from 9 animals was dissected into 5 separate sections: outer fold (OF), middle fold (MF), inner fold (IF), ventral mantle tissue (VM) and dorsal mantle tissue (DM). Total RNA was extracted from these tissues and pooled across subjects in order to reduce the effect of biological variation; such that 3 individuals were pooled together totaling 3 pooled replicate samples for each tissue. All the biologically pooled tissue types were compared against a common reference in which total RNA from all tissues types and all nine animals was equally pooled. A total of 30 dual channel microarrays hybridizations were performed and analyzed.
Project description:Many bivalve species produce groups of strong proteinaceous byssal threads to rigidly attach to underwater substrates. Fibres like these have potential applications as biomedical materials due to their unique mechanical characteristics. The byssus and byssal thread producing glands of Pinctada maxima have not yet been characterised. RNA was isolated from P. maxima foot and byssal stem region tissues and sequenced using the Illumina platform. A de novo reference transcriptome comprising 34,281 contiguous sequences was assembled, and tissue replicates were mapped against the reference for quantitative analysis. Tryptic digests of byssal threads were analysed by LC-MS/MS. The resultant peptides were matched to 62 protein sequences derived from our reference transcriptome. Components of the byssus were identified for further characterisation, including a highly expressed perlucin-like foot protein (Pmfp1) and a recently identified protein that we refer to herein as glycine-rich thread (GRT) protein. This work provides principal knowledge on the molecular components of the byssus for P. maxima and the foot ultrastructure involved in the creation of byssal threads. This study advances our knowledge of byssus biosynthesis in non-mytilids, providing a platform for the design of new marine biopolymers.