Poster: Transcription Regulation

Abs # 1037: Transcribed region of an upstream gene contains regulatory elements for developmental- and tissue-specific expression of Arabidopsis ZWI/KCBP gene

Presenter:	Reddy, Vaka S., vaka@lamar.colostate.edu
Authors	Reddy, Vaka S. (A)   Reddy, Anireddy S. N. (A) (B)
Affiliations:	(A): Dept. of Biology, Colorado State University (B): Program in Cell and Molecular Biology

Functional studies with the ZWI (ZWICHEL) gene that encodes kinesin-like calmodulin-binding protein indicate its involvement in trichome morphogenesis and cell division. To identify the regulatory elements and expression pattern of ZWI, we generated transgenic plants with a GUS reporter gene driven by different lengths of the ZWI 5’ and 3’ regions or both together. The 5’ region contains varying lengths of the transcribed CHY (b-hydoxyisobutyryl-CoA hydrolase 1) gene that is upstream of ZWI and a 162 bp intergenic region. In transgenic plants with -433::GUS, reporter gene expression was observed only at the root-hypocotyl junction and in root hairs whereas plants with -699::GUS alone or together with the 3’ region showed enhanced GUS expression in the entire root of light-grown seedlings including root meristems as well as in other cell types such as trichomes and pollen at various developmental stages. However, no GUS expression was detected in roots of dark-grown seedlings containing -699::GUS alone or with the 3’ region but not in -433::GUS. Further, in IAA treated dark-grown seedlings with -699::GUS, the GUS expression was restricted to specific regions at the base of the lateral root. However, the 3’ region alone or in combination with the 5’ region did not effect GUS expression in any tissues or in the presence of IAA, suggesting that the tested 3’ region (~3 kb) does not have any regulatory role. The expression pattern of GUS in transgenics is further supported by the presence of the known light-responsive I-box/GATA and pollen-, root- and metaphase-specific activator cis-elements in the 726 bp upstream sequence. Together, these results indicate that the regulatory elements for developmental- and tissue-specific expression of ZWI reside in its upstream CHY gene.