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Biomedical subjects

Erich Grotewold

Publications and source records attributed to Erich Grotewold.

22 records · Page 2Linked to original sources
PubMed2003

Recently duplicated maize R2R3 Myb genes provide evidence for distinct mechanisms of evolutionary divergence after duplication.

R2R3 Myb genes are widely distributed in the higher plants and comprise one of the largest known families of regulatory proteins. Here, we provide an evolutionary framework that helps explain the origin of the plant-specific R2R3 Myb genes from widely distributed R1R2R3 Myb genes, through a series of well-established steps. To understand the routes of sequence divergence that followed Myb gene duplication, we supplemented the information available on recently duplicated maize (Zea mays) R2R3 Myb genes (C1/Pl1 and P1/P2) by cloning and characterizing ZmMyb-IF35 and ZmMyb-IF25. These two genes correspond to the recently expanded P-to-A group of maize R2R3 Myb genes. Although the origins of C1/Pl1 and ZmMyb-IF35/ZmMyb-IF25 are associated with the segmental allotetraploid origin of the maize genome, other gene duplication events also shaped the P-to-A clade. Our analyses indicate that some recently duplicated Myb gene pairs display substantial differences in the numbers of synonymous substitutions that have accumulated in the conserved MYB domain and the divergent C-terminal regions. Thus, differences in the accumulation of substitutions during evolution can explain in part the rapid divergence of C-terminal regions for these proteins in some cases. Contrary to previous studies, we show that the divergent C termini of these R2R3 MYB proteins are subject to purifying selection. Our results provide an in-depth analysis of the sequence divergence for some recently duplicated R2R3 Myb genes, yielding important information on general patterns of evolution for this large family of plant regulatory genes.

Amino Acid Sequence↗
PubMed2003

Metabolite profiling as a functional genomics tool.

Plants accumulate a very large number of small molecules (phytochemicals) with important functions in the ecology of plants and in the protection against biotic and abiotic stress conditions. Little is known on how phytochemical biosynthetic pathways are regulated, which is a key step to successfully engineering plant metabolism. Plant natural products are usually not essential, and genetic analyses often fail to identify phenotypes associated with the absence of these compounds. We have investigated the use of metabolite profiling of plant cells in culture to establish the function of transcription factors suspected to control plant metabolic pathways.

Cell Culture Techniques↗
PubMed2002

Transposon insertions in the promoter of the Zea mays a1 gene differentially affect transcription by the Myb factors P and C1.

The understanding of control of gene regulation in higher eukaryotes relies heavily on results derived from non-in vivo studies, but rarely can the significance of these approximations be established in vivo. Here, we investigated the effect of Mutator and Spm insertions on the expression of the flavonoid biosynthetic gene a1, independently regulated by the transcription factors C1 and P. The a1-mum2 and a1-m2 alleles carry Mu1 and Spm insertions, respectively, in a cis-element (ARE) of unknown function located between the P- and C1-binding sites. We show that the insertions of Mu1 and Spm similarly influence the expression of a1 controlled by C1 or P. The P-controlled a1 expression in a1-m2 is Spm dependent, and the mutant phenotype of a1-mum2 is suppressed in the pericarp in the absence of the autonomous MuDR element. Footprints within the ARE affect the regulation of a1 by C1 and P differently, providing evidence that these factors control a1 expression using distinct cis-acting regulatory elements. Together, our findings contribute significantly to one of the best-described plant regulatory systems, while stressing the need to complement with in vivo experiments current approaches used for the study of control of gene expression.

Alcohol Oxidoreductases↗