RT Journal Article
SR Electronic
T1 An Untranslated <em>cis</em>-Element Regulates the Accumulation of Multiple C<sub>4</sub> Enzymes in <em>Gynandropsis gynandra</em> Mesophyll Cells
JF The Plant Cell
JO Plant Cell
FD American Society of Plant Biologists
SP 454
OP 465
DO 10.1105/tpc.15.00570
VO 28
IS 2
A1 Williams, Ben P.
A1 Burgess, Steven J.
A1 Reyna-Llorens, Ivan
A1 Knerova, Jana
A1 Aubry, Sylvain
A1 Stanley, Susan
A1 Hibberd, Julian M.
YR 2016
UL http://www.plantcell.org/content/28/2/454.abstract
AB C4 photosynthesis is a complex phenotype that allows more efficient carbon capture than the ancestral C3 pathway. In leaves of C4 species, hundreds of transcripts increase in abundance compared with C3 relatives and become restricted to mesophyll (M) or bundle sheath (BS) cells. However, no mechanism has been reported that regulates the compartmentation of multiple enzymes in M or BS cells. We examined mechanisms regulating CARBONIC ANHYDRASE4 (CA4) in C4 Gynandropsis gynandra. Increased abundance is directed by both the promoter region and introns of the G. gynandra gene. A nine-nucleotide motif located in the 5′ untranslated region (UTR) is required for preferential accumulation of GUS in M cells. This element is present and functional in three additional 5′ UTRs and six 3′ UTRs where it determines accumulation of two isoforms of CA and pyruvate,orthophosphate dikinase in M cells. Although the GgCA4 5′ UTR is sufficient to direct GUS accumulation in M cells, transcripts encoding GUS are abundant in both M and BS. Mutating the GgCA4 5′ UTR abolishes enrichment of protein in M cells without affecting transcript abundance. The work identifies a mechanism that directs cell-preferential accumulation of multiple enzymes required for C4 photosynthesis.GlossaryMmesophyllBSbundle sheathCAcarbonic anhydraseUTRuntranslated regionMUG4-methylumbulliferone-glucuronidemiRNAmicroRNAMSMurashige and SkoogMU4-methylumbulliferone