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Significance of consensus CYC‐binding sites found in the promoters of both ChCYC and ChRAD genes in Chirita heterotricha (Gesneriaceae)
Author(s) -
YANG Xia,
CUI Hong,
YUAN ZuLi,
WANG YinZheng
Publication year - 2010
Publication title -
journal of systematics and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.249
H-Index - 46
eISSN - 1759-6831
pISSN - 1674-4918
DOI - 10.1111/j.1759-6831.2010.00086.x
Subject(s) - gene , antirrhinum , promoter , biology , genetics , antirrhinum majus , consensus sequence , gene expression , arabidopsis , mutant , peptide sequence
CYC ‐like genes are widely conserved in controlling floral dorsoventral asymmetry (zygomorphy) through persistent expression in corresponding domains in core eudicots. To understand how CYC ‐like gene expression is maintained during flower development, we selected Chirita heterotricha as a material and isolated the promoter sequences of the ChCYC1C and ChCYC1D genes, homologs of CYC , by inverse polymerase chain reaction. Further promoter analyses led to the identification of a putative cis ‐regulatory element in each promoter matching the consensus DNA binding site for Antirrhinum CYC protein: GGCCCCTC at −165 for ChCYC1C , and GG at −163 for ChCYC1D . This indicates that both the ChCYC1C and ChCYC1D genes have probably evolved autoregulatory loops to sustain their expression in developing flowers. We also isolated the coding and promoter sequences of the ChRAD gene, a homolog of Antirrhinum RAD . Promoter analysis showed that the ChRAD gene promoter also contained a putative CYC‐binding site (GGCCCAC at −134). Therefore, ChRAD is likely a direct target of the ChCYC1 genes, which is similar to Antirrhinum RAD . These results imply that the establishment of floral zygomorphy in Chirita may have been achieved by the evolution of an autoregulatory loop for CYC ‐like genes, which was probably accompanied by simultaneous co‐option of the RAD ‐like gene into their regulatory network.