The Antarctic clam Laternula elliptica lives almost permanently below 0 °C and therefore is a valuable and tractable model to study the mechanisms of biomineralisation in cold water. The present study employed a multidisciplinary approach using histology, immunohistochemistry, electron microscopy, proteomics and gene expression to investigate this process. Thirty seven proteins were identified via proteomic extraction of the nacreous shell layer, including two not previously found in nacre; a novel T-rich Mucin-like protein and a Zinc-dependent metalloprotease. In situ hybridisation of seven candidate biomineralisation genes revealed discrete spatial expression patterns within the mantle tissue, hinting at modular organisation, which is also observed in the mantle tissues of other molluscs. All seven of these biomineralisation candidates displayed evidence of multifunctionality and strong association with vesicles, which are potentially involved in shell secretion in this species.
VAS was funded by a NERC DTG studentship (Project Reference: NE/J500173/1) to the British Antarctic Survey. MSC was financed by NERC core funding to the British Antarctic Survey. We would like to thank Jeremy Skepper for advising us on TEM procedures and processing the mantle tissue samples prior to TEM, Elizabeth M. Harper for advice on Laternula elliptica mantle anatomy for the schematic, Jamie Oliver for technical help with digitising the schematic, Deborah M. Power for in situ hybridisation advice, Valerie J. Smith for advice on immunology and histology, Lloyd S. Peck for vesicle discussions and critical reading of the manuscript and the dive team at Rothera research station, Antarctica for support in animal collection. Diving oversight was provided by the NERC National Facility for Scientific Diving, Oban.
- environmental sciences
- gene expression