Stephen Mayfield
Lab Overview
Our lab studies translational regulation in the eukaryotic algae C. reinhardtii
and the use of this algae for the production of human therapeutic proteins.
Over the last year we have achieved expression of a human anti-anthrax antibody
in algae, and expression of a bovine serum amyloid protein to very high levels,
5% of total protein. Last year we solved the structure of the cytoplasmic ribosome
to 20 A, and more recently we have solved the structure of the chloroplast
ribosome to below 20 A. These structure should help us understand the basic
tenets of translation in plants.
Highlight
Structure of the Chloroplast Ribosome reveals unique solvent-exposed domains
likely involved in translation regulation.
Using single particle reconstruction from cryo-electron micrograph images
we
have calculated the structure of the chloroplast ribosome to 20Å.
The small
subunit of the chloroplast ribosome from C. reinhardtii has a large
solvent-exposed domain not present on evolutionarily similar bacterial
ribosomes. This chloroplast-unique domain is found in close proximity to
the
initial site of mRNA interaction with the ribosome. In bacteria this is the
site of the Shine-Dalgarno interaction that positions bacterial mRNA in the
appropriate register for translation initiation, which suggests that this
chloroplast-unique structural domain may have a similar function for the
chloroplast ribosome.
2005 Publications
Barnes, D., Franklin, S., Schultz, J., Henry, R., Brown, E.,
Coragliotti, A., Mayfield, S.P. (2005) Contribution of 5’ and 3’ untranslated
regions in the expression of Chlamydomonas reinhardtii chloroplast genes. Molec.
Genet. and Genom. 18; 1-12
Manuell, A., Yamaguchi, K., Haynes, P., Milligan, R., Mayfield, S.P. (2005)
The composition and structure of 80S ribosome from the green alga Chlamydomonas
reinhardtii: 80S ribosomes are conserved in plants and animals. Jour, Mol.
Biol. 351; 266-279
Somanchi A., Barnes, D., Mayfield, S.P. (2005) Characterization of a Chlamydomonas
reinhardtii nuclear gene, tad1, required for translation initiation of the
chloroplast psbA mRNA. Plant J. 42: 341-352.
Mayfield, S.P., Franklin, S.E. (2005) Expression of Human Antibodies in Eukaryotic
Micro-algae. Vaccine, 23; 1828-32
Franklin, S.E., Mayfield, S.P. (2005) Recent developments in the production
of human therapeutic proteins in eukaryotic algae Expert Opin Biol Ther. 5;225-235
Fletcher, S.P., Muto, M., Mayfield, S.P. (2006) Optimization of recombinant
protein expression in the chloroplast of green algae. In: Transgenic microalgae
as green cell factories. In press
