Dr. Adam M. Reitzel
Assistant Professor, Department of Biology University of North Carolina, Charlotte,N.C.
My current research utilizes the starlet sea anemone, Nematostella vectensis, to study the evolution and transcriptional regulation of stress response pathways.Nematostella is a useful emerging model species to study these questions for at least three reasons: 1) as a cnidarian, this anemone is evolutionarily well-positioned as a representative outgroup to traditional studies in vertebrates and insects; 2) the genome has been sequenced and extensive molecular tools have been developed, including gene expression profiling, in situ hybridization, and knockdowns; and 3) it is a broadly distributed, estuarine specialist occupying high marsh environments, and thus is naturally exposed to habitat perturbations and point sources of contaminants. I am currently pursing three research directions that address a suite of questions and use a diverse set of techniques.
- Transcriptional Profiling of Nematostella in Response to Environmental Stressors.
Estuaries continue to be impacted by diverse stressors including coastal development, climate change and anthropogenic contaminants (e.g. heavy metals, polycyclic aromatic hydrocarbons and endocrine disruptors). Currently, I am assessing transcriptional responses of Nematostella to two stressors (temperature, toxic metals) using (1) quantitative PCR (qPCR) for candidate genes identified with comparative genomics and (2) transcriptional profiling with suppressive subtractive hybridization and microarrays. Each of these techniques has identified conserved and novel molecular players and expression patterns, likely involved in mediating the organismal response to these common stressors.
- Evolution and Function of Nuclear Receptors in Basal Metazoans.
Nuclear receptors (NRs) are essential transcription factors restricted to animals that are involved in development, physiology, and environmental signal reception. The evolutionary history of this superfamily and the functions of particular NRs are poorly characterized in basal metazoans. To address these questions, firstly, in collaboration with Dr. Tarrant, we are characterizing the distribution of NR orthologs in various basal metazoans (cnidarians, placozoans, sponges) using bioinformatic and phylogenetic techniques. Secondly, we are characterizing the expression of these genes with qPCR and in situ hybridization. Finally, we are determining the potential function of these NRs via in vitro protein-protein interaction assays and in vivo knock-downs for particular NRs.
- Geographic Distribution and Population Genetic Structure of Nematostella.
Due to its small size and ecological distribution in high marsh, infaunal habitats, accurate records for distribution of Nematostella are surely incomplete. For locations that have been characterized, collaborators and I have completed a series of studies characterizing the population genetic structure of Nematostella. These studies have shown a high degree of genetic structure among populations that have extremely low gene flow and thus are genetically isolated. In combination with environmental monitoring, these data suggest that particular populations are vulnerable to local extinction events via anthropogenic habitat restructuring, which may not be recolonized after habitat restoration. Through an on-line video and contact with estuarine biologists throughout North America, we continue to identify novel populations, which provide a more complete assessment of the distribution of this species. In tandem with the distribution of populations, we are also identifying geographically restricted polymorphisms through complete bioinformatic surveys (Reitzel et al. in review) and an ongoing survey of single nucleotide polymorphisms utilizing pyrosequencing for a panel of individuals. As we continue to gather data on population distribution, gene flow, and location-specific alleles, we will extend our preliminary work on identifying locally adapted populations, with efforts to characterize the specific polymorphisms that underlie these adaptations.