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Title: DIFFERENTIAL EXPRESSION OF SUGARCANE POLYUBIQUITIN GENES AND ISOLATION OF PROMOTERS FROM TWO HIGHLY-EXPRESSED MEMBERS OF THE GENE FAMILY

Author
item WEI, HAIRONG
item Albert, Henrik
item Moore, Paul

Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/1999
Publication Date: N/A
Citation: Wei, H., Albert, H.H., Moore, P.H. 1999. Differential expression of sugarcane polyubiquitin genes and isolation of promoters from two highly-expressed members of the gene family. Journal of Plant Physiology 155:513-519.

Interpretive Summary: The number of constitutive gene promoters available for research and biotech crop improvement in monocot plants is limited. In a collaborative project involving UH and ARS researchers, expression of four sub-families of polyubiquitin genes was determined in sugarcane. Two gene promoters were isolated which consistently produced high levels of transient expression in monocot tissues. These promoters provide additional tools for scientists working to study and improve monocot plants.

Technical Abstract: To identify potential strong constitutive promoters, accumulation of polyubiquitin mRNA in sugarcane was studied using gene-specific probes from five sugarcane polyubiquitin cDNA clones. Based on comparisons of 3' untranslated regions, these cDNAs can be grouped into four sub-groups within the sugarcane polyubiquitin multi-gene family. RNA gel blot and reverse northern experiments indicate that these sub-groups differ in constitutive expression levels and response to heat shock. One sub-group, homologous to cDNAs scubi241 and scubi511, was found to have the highest level of constitutive expression and to be little affected by heat shock. Genomic clones belonging to this sub-group were isolated; two of these clones, ubi4 and ubi9, were found to differ in the number of protein coding repeats but were highly similar in overall structure and in the sequence of DNA flanking the transcribed region. Both genes contain a single large intron located immediately upstream of the translation start codon. Transient expression experiments showed that the cloned promoters are sufficient to drive high levels of GUS expression in sugarcane suspension cells and in tobacco leaves.