Our Research Focus
Our research centers on Chlamydomonas reinhardtii, a photosynthetic aquatic organism. With its well-characterized genetics and relatively stable expression system, C. reinhardtii has become a widely used model organism for transgenic experiments. In this project, we explored several aspects of C. reinhardtii and achieved notable progress.
Cultivation of C. reinhardtii
At the outset, cultivating C. reinhardtii posed significant challenges. To gain experience, we first used another more easily cultured alga, Tetraselena obliquus, as a pre-experiment before transitioning to the formal cultivation of C. reinhardtii. We primarily worked with two strains:
CC-124 (wild type): This strain has an intact cell wall and is robust, making it suitable for long-term cultivation, though with relatively low transformation efficiency.
UVM-4 (laboratory mutant): This strain lacks a cell wall, which facilitates efficient transformation but renders it more fragile.
The complementary characteristics of these two strains provided flexibility for our experiments. Related results can be found on our Results page.
Registration of New Parts
During the course of the project, we designed and registered new parts derived from our research on C. reinhardtii. *
| Part ID | Name | Length | Description | Link |
|---|---|---|---|---|
| BBa_25CTFPLO | PsaD promoter (variant of BBa_K3002001, A to T at bp 242; remove 2 bp at 5' end) | 812 bp | Variant of the PsaD promoter from C. reinhardtii, based on iGEM part BBa_K2003001, with a single base substitution (A to T at position 242) and a 2 bp truncation at the 5' end. | https://registry.igem.org/parts/bba-25ctfplo |
| BBa_2588Q1R8 | Cpn60C CDS (Chlamydomonas reinhardtii) v2 | 1713 bp | Coding sequence for mitochondrial chaperonin 60C from C. reinhardtii. Synonymous substitutions remove BsaI and PstI sites for RFC10/Type IIS compliance, amino acid sequence unchanged. This part is an updated version of part # BBa_250W16TT. The updated sequence removes 2 PstI sites and 1 BsaI site. | https://registry.igem.org/parts/bba-2588q1r8 |
| BBa_25OFL0IY | PsaD 3'UTR terminator (Chlamydomonas reinhardtii) | 623 bp | Non-coding 3"UTR from Chlamydomonas reinhardtii PsaD gene. Functions as a transcription terminator. Edited to remove BsaI/SapI sites for RFC10/TypeIIS compliance. | https://registry.igem.org/parts/bba-25ofl0iy |
| BBa_25NM4APY | CPN60C Overexpression Composite (v2): PsaD promoter + CPN60C CDS + PsaD 3'UTR terminator (“Plasmid A”) |
3256 bp | This composite part expresses the Chlamydomonas reinhardtii mitochondrial chaperonin CPN60C under control of the PsaD promoter (corrected sequence) and the PsaD 3'UTR terminator. The CPN60C chaperonin assists in protein folding within mitochondria and may enhance thermal resilience and protein stability under stress. In the original plasmid, a short non-coding spacer sequence (GAATTCTTAGATCT, containing EcoRI/BglII) followed the stop codon before the PsaD 3′UTR. To maintain RFC10 compatibility, this spacer was omitted in the registered composite. The protein product and functional terminator are unaffected. |
https://registry.igem.org/parts/bba-25nm4apy |
| BBa_2514TH1Z | HSP70A-RBCS2 fusion promoter | 647 bp | The HSP70A-RBCS2 fusion promoter drives strong, constitutive expression in the nucleus of Chlamydomonas reinhardtii. This variant differs from the previously registered version by eight base-pair substitutions/insertions located outside the known core motifs. These changes do not alter function and were verified to maintain RFC10 and Type IIS compatibility. | https://registry.igem.org/parts/bba-2514th1z |
| BBa_25XLGOPS | Cpn60C Overexpression Translational Unit: HSP70A-RBCS2 + Cpn60C + RBCS2 terminator (v2) | 2604bp | Expression cassette for the mitochondrial chaperonin Cpn60C driven by the 22bp-corrected HSP70A-RBCS2 fusion promoter and terminated by the RBCS2 3'UTR. | https://registry.igem.org/parts/bba-25xlgops |
* Note: The construction of plasmids and optimization of the expression cassette designs were carried out with the support of external experts. Details of their contributions can be found in the “Design & Description” file linked in the Registry, as well as on the Attribution, Engineering, and Experiments pages of our Team Wiki.
Research on the CPN60C Protein
We investigated the mitochondrial chaperonin protein CPN60C in C. reinhardtii. CPN60C is homologous to CPN60α and CPN60β, which function in chloroplasts, yet it has been far less studied. Under heat shock conditions, CPN60C assists in correct protein folding and mitigates misfolding, thereby protecting algal cells, enhancing survival under heat stress, and sustaining photosynthetic efficiency. Our experiments demonstrated that C. reinhardtii transformants overexpressing CPN60C exhibited improved survival under heat stress. These findings provide new insights into the mechanisms underlying heat tolerance in C. reinhardtii.
Promoting Knowledge about C. reinhardtii
Through public engagement, we found that knowledge of C. reinhardtii is limited, with many people conflating it with “algae” in general. To address this, we organized educational activities in schools and communities to highlight the characteristics and research significance of C. reinhardtii, thereby fostering greater public understanding of this model organism.