Abundant expression in vascular tissue of plant TAF10, an orthologous gene for TATA box-binding protein-associated factor 10, in Flaveria trinervia and abnormal morphology of Arabidopsis thaliana transformants on its overexpression.

TAF10 is one of the TATA box-binding protein-associated factors (TAFs), which constitute the TFIID complex. We isolated a plant TAF10 ortholog from a Flaveria trinervia cDNA library, and named it ftTAF10. The ftTAF10 polypeptide contains a histone-fold motif, which is highly conserved among the TAF10s of other organisms. A transiently expressed green fluorescent protein (GFP) fusion protein was translocated into the nuclei of onion epidermal cells, suggesting that the ftTAF10 functions in nuclei. The transcript level was higher in stems and roots than in leaves, and in situ hybridization of F. trinervia seedlings revealed that the ftTAF10 transcript is accumulated abundantly in vascular tissues of hypocotyls, in the central cylinder of roots, and slightly in bundle sheath cells of leaves. Overexpression of ftTAF10 in Arabidopsis under the cauliflower mosaic virus 35S promoter caused two kinds of abnormal morphology, limitation of the indeterminate inflorescence and production of deformed leaves. These results indicate the possibility that ftTAF10 is a plant 'selective TAF' involved in the expression of a subset of vascular abundant genes, and that its appropriate gene expression is necessary for normal development.