A 3' stem/loop structure of the Chlamydomonas chloroplast atpB gene regulates mRNA accumulation in vivo.

Abstract

The Chlamydomonas reinhardfii chloroplast afp6 mRNA contains sequences at its 3' end that can form a complex stem/loop structure. Deletions of part or all of this sequence in transformed C. reinhardfii cells led to decreased atp6 mRNA accumulation, whereas transcription rates were unaffected. The reduction of mRNA to 20% to 35% of wild-type levels in transformants without 3' stem/loops was correlated with the accumulation of atp6 mRNA that was heterogeneous in size. These results indicated that RNA secondary structures function both in mRNA stabilization and in 3' end formation in C. reinhardtii chloroplasts. Furthermore, deletion of the stem/loop resulted in a decrease in the steady-state level of the ATPase 8-subunit to approximately 60% of wild-type levels, suggesting that translational and/or post-translational mechanisms may influence the steady-state level of the afp6 gene product.

Chloroplast RNA processing and stability

“…This 3 0 UTR contains a stem-loop structure which has a significant influence on both correct 3 0 processing and RNA stabilization, not unlike the situation for the psaB mRNA (Stern et al 1991;Lee et al 1996). This 3 0 UTR contains a stem-loop structure which has a significant influence on both correct 3 0 processing and RNA stabilization, not unlike the situation for the psaB mRNA (Stern et al 1991;Lee et al 1996).…”

CHLAMYDOMONAS REINHARDTII AS THE PHOTOSYNTHETIC YEAST

“…This region generally contains a conspicu ous inverted repeat whose role in RNA stability and RNA 3' end maturation has been demonstrated for the atpB transcript, encoding the � subunit of A TP synthase (86). This region generally contains a conspicu ous inverted repeat whose role in RNA stability and RNA 3' end maturation has been demonstrated for the atpB transcript, encoding the � subunit of A TP synthase (86).…”

Biomass and Biofuels from Microalgae

“…Although chloroplast gene expression is usually regulated at the translational level (Barnes et al 2005;Eberhard et al 2002;Nickelsen 2003;Rasala et al 2010Rasala et al , 2011Zerges 2000), choice of promoter and 5′ UTRs sequences is of importance due to potential feedback regulations which can interfere with the heterologous protein expression and mRNA stability Hauser et al 1996;Manuell et al 2007). The 5′ UTRs are believed to regulate ribosome association, transcript stability and the rate of translation (Barnes et al 2005;Marin-Navarro et al 2007;Salvador et al 1993;Zou et al 2003) while 3′ UTRs influence mRNA stability (Herrin and Nickelsen 2004;Lee et al 1996;Monde et al 2000;Stern et al 1991) or may interact with 5′ UTRs (Katz and Danon 2002).…”