title: Transcriptomics provides insight into Mytilus galloprovincialis (Mollusca: Bivalvia) mantle function and its role in biomineralisation.
abstract: The mantle is an organ common to all molluscs and is at the forefront of the biomineralisation process. The present study used the Mediterranean mussel (Mytilus galloprovincialis) as a model species to investigate the structural and functional role of the mantle in shell formation. The transcriptomes of three regions of the mantle edge (umbo to posterior edge) were sequenced using Illumina technology which yielded a total of 61,674,325 reads after adapter trimming and filtering. The raw reads assembled into 179,879 transcripts with an N50 value of 1086bp. A total of 1363 transcripts (321, 223 and 816 in regions 1, 2 and 3, respectively) that differed in abundance in the three mantle regions were identified and putative function was assigned to 54% using BLAST sequence similarity searches (cut-off less than 1e(-10)). Morphological differences detected by histology of the three mantle regions was linked to functional heterogeneity by selecting the top five most abundant Pfam domains in the annotated 1363 differentially abundant transcripts across the three mantle regions. Calcium binding domains dominated region two (middle segment of the mantle edge). Candidate biomineralisation genes were mined and tested by qPCR. This revealed that Flp-like, a penicillin binding protein potentially involved in shell matrix maintenance of the Pacific oyster (Crassostrea gigas), had significantly higher expression in the posterior end of the mantle edge (region one). Our findings are intriguing as they indicate that the mantle edge appears to be a heterogeneous tissue, displaying structural and functional bias.
authors.affiliation: Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, University of Algarve, Gambelas Campus, 8005-139 Faro, Portugal. Electronic address: nallan@ualg.pt.
authors.forename: Nadège A
authors.initials: NA
authors.lastname: Bjärnmark
authors.affiliation: British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK; University of Edinburgh, Institute of Evolutionary Biology, Ashworth Laboratories, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK.
authors.forename: T
authors.initials: T
authors.lastname: Yarra
authors.affiliation: Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, University of Algarve, Gambelas Campus, 8005-139 Faro, Portugal.
authors.forename: A M
authors.initials: AM
authors.lastname: Churcher
authors.affiliation: Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, University of Algarve, Gambelas Campus, 8005-139 Faro, Portugal.
authors.forename: R C
authors.initials: RC
authors.lastname: Felix
authors.affiliation: British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK.
authors.forename: M S
authors.initials: MS
authors.lastname: Clark
authors.affiliation: Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, University of Algarve, Gambelas Campus, 8005-139 Faro, Portugal. Electronic address: dpower@ualg.pt.
authors.forename: D M
authors.initials: DM
authors.lastname: Power
mesh_terms: D060105:Animal Shells / Q000254:growth & development; D000818:Animals; D002113:Calcification, Physiologic; D023281:Genomics; D049878:Mytilus / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D017422:Sequence Analysis, DNA; D059467:Transcriptome
keywords: Gene expression; Multi-functional; Pfam; RNA-seq; Trinity