Molecular Physiology / Functional Genomics

Contact Investigator: Dr. Magnus Lucassen

Temperature as a key environmental factor shapes the physiology of ectothermic marine animals and thereby their biogeography and mode of life in various climates and ecosystems. Our research addresses the genetic underpinning of climate dependent physiological and ecological functions. Molecular mechanisms defining thermal limits as well as acclimation or adaptation to temperature are being studied at the level of individual proteins or protection mechanisms. Since thermal windows of individual molecules largely exceed the thermal limits of the whole animal, thermal limits are most probably set at the level of integration of molecular into functional units and networks at higher levels of organisation. Therefore we also aim to investigate how molecular functions contribute to climate sensitivity as well as acclimation and adaptation processes from a whole organism point of view. Evolutionary adaptation to various climates is addressed in comparative studies carried out with populations of the same species in climatic gradients or with congeneric species living in different climatic zones. For example, member species of the fish family Zoarcidae (eelpouts) inhabit temperate, subpolar and polar waters and represent a model system for the study of evolutionary adaptation versus seasonal acclimatisation to temperature. Our previous studies have demonstrated the high conservation level of functional genes in different eelpouts from boreal and Antarctic waters, corroborating that these species are excellent models in comparative functional genomics studies.

• How does the repertoire of the functional genome change during adaptation to the extreme but stable environment of the Antarctic and how do the respective adaptation strategies differ from those in environments, which face the organisms with large and often fast changes in key abiotic factors?
• Which are the signals and regulatory networks defining adaptation and how are these networks differentiated in different environments?
• How does genetic information integrate into functional units within an increasingly complex system (from molecule, organelle, cell, tissue to organism) and define species success?

To answer these questions, we combine hypothesis-driven functional and discovery-based genomic approaches:
Functional approaches are used to characterize e.g. key processes of energy metabolism at all levels from gene expression to protein function. Here, we mainly focus on aerobic capacities, the regulation of mitochondrial biogenesis and the signals involved. Molecular adjustments in ion and pH regulation are analysed not only in the context of temperature adaptation but also in the face of increasing CO2 levels in marine surface waters. Furthermore, by comparing regulatory genes of important signal pathways (e.g. O2-homeostasis) we investigate the evolution of protein function and their involvement in the process of adaptaptation.
Genomic approaches are used to identify differentially expressed genes and new candidate genes with so far unknown functions. By comparing different tissues and the responses to other abiotic key factors like CO2 and O2 we aim to identify gene clusters and networks, which define sensitivity and adaptability to environmental change. Emerging candidate genes will then be subjected to functional characterization.

• Isolation and characterisation of functional genes from marine vertebrates and invertebrates by RT-PCR, RACE, cloning, DNA sequencing, expression.
• Quantification of mRNA by Realtime-PCR, RNase protection assay, Northern blotting.
• Construction of normalized and subtractive cDNA libraries.
• Protein characterisation and quantification by immunological methods.
• Radioiosotopic methodology for the detection and quantification of gene and protein expression, studies of enzyme functions.
• Integration of molecular, biochemical, cellular and organismal approaches.

• Fully equipped genetic laboratory with permission to work at S1-level
• Realtime PCR (ABI7500)
• Phosphorstorage Imagesystem (Fuji FLA 5000 with three lasers)
• Cooled CCD camera system (Fuji LAS 1000)
• Several gradient PCR cyclers

Dr. Magnus Lucassen