Chlamydomonas Research Projects:
Chlamydomonas reinhardtii is a unicellular green alga that has been used as a model system for the study of, among other things, photosynthesis and chloroplast biogenesis. Although in most respects it is similar to that in higher plants, photosynthetic function in Chlamydomonas is dispensable and mutants can be maintained on a carbon source such as acetate. Other experimental advantages of Chlamydomonas are the ease with which it can be cultured in the laboratory, and the ability to combine facile genetics with the techniques of modern molecular biology (Weeks, DP 1992 Chlamydomonas: An increasingly powerful model plant cell system. The Plant Cell 4:871-878). Well characterized mutants are maintained at a central depository (The Chlamydomonas Genetics Center at Duke University). The Genetics Center also serves as a general resource and discussion site for the relatively small and intimate community of Chlamydomonas researchers.
There
are three laboratories at the Beadle Center in Lincoln whose research
focuses on various aspects of Chlamydomonas Biology. The
combined strengths of these laboratories within the Beadle Center provide
an excellent opportunity for studies of various biological problems that
use Chlamydomonas as a model organism.
Research with Chlamydomonas in our laboratory can be divided into two broad areas. One is the development of improved tools and reagents for nuclear transformation and gene isolation from Chlamydomonas. An indexed cosmid library of wild-type Chlamydomonas DNA was created to allow for rapid isolation of genes by direct genomic complementation of mutants (Zhang, H, PL Herman, DP Weeks 1994). Gene isolation through genomic complementation using an indexed library of Chlamydomonas reinhardtii DNA. Plant Mol Biol 24:663-672; Funke, RP, JL Kovar, DP Weeks 1997a Intracellular carbonic anhydrase is essential to photosynthesis in Chlamydomonas reinhardtii at atmospheric levels of CO2: Demonstration via genomic complementation of the high CO2-requiring mutant ca-1. Plant Physiol. 114:237-244). More recently, a gene has been isolated that has the potential to serve as a homologous dominant selectable marker for nuclear transformation by conferring resistance to a herbicide (Funke, RP, JL Kovar, DP Weeks 1997b Nucleotide sequence of a cDNA encoding Chlamydomonas reinhardtii acetolactate synthase. Plant Physiol. 115, 1288).
The other broad area of Chlamydomonas
research in the Weeks laboratory centers on the carbon concentrating
mechanism. Although the presence of an active carbon uptake
mechanism in many aquatic photosynthetic organisms has been known for
many years, very few of the essential components have been isolated.
The existence of well characterized mutants in carbon accumulation, together
with the recently acquired ability to isolate genes from Chlamydomonas
by genomic complementation, provides a new opportunity to advance understanding
of this fundamental process (Funke, RP, JL Kovar, DP Weeks 1997a,
see above). The long range goal is to use information gained in
this research for the elucidation of structures and mechanisms responsible
for enhancing CO2 availability in Chlamydomonas and
other photosynthetic organisms. 
A variety of molecular, genetic and biochemical approaches are being taken to unvail unknown aspects of the carbon concentrating mechanism. Opportunities exist for graduate students and post-docs to make contributions in either of the Chlamydomonas projects in the laboratory.
