Figure 4.
Expression and processing of UBQ-LUC fusions in transgenic tobacco. A, RNA gel-blot analysis of 10 μg of total RNA isolated from young leaves expressing LUC alone or as a UBQ fusion (lanes UBQ-LUC). Left, RNA blot hybridized with a LUC-specific probe. Right , RNA blot hybridized with a UBQ-specific probe. The arrowhead indicates migration position of the UBQ-LUC transcript. RNAs of 1.6 and 0.8 kb (*) that also hybridize with the UBQ probe correspond in size to transcripts derived from endogenous tobacco UBQ genes. B, Immunoblot analysis of plants expressing LUC or UBQ-LUC. Soluble protein (10 μg) from young leaves was subjected to SDS-PAGE and LUC protein was visualized by immunoblotting with LUC antibodies. Lane UBQ-LUC + LUC, Equal amounts of leaf extract from plants expressing UBQ-LUC and LUC mixed prior to electrophoresis. Lane NT, Sample from a nontransformed plant. C, Accumulation of LUC protein in plants transformed with either the LUC or the UBQ-LUC vector. Top and middle, Immunoblot analysis with LUC antibodies of soluble leaf protein extracted from randomly selected T0 plants independently transformed with either the UBQ-LUC or the LUC vector. Arrowheads indicate the position of mature LUC. Bottom, Distribution profile of LUC activity in a population of independently transformed tobacco: 64 UBQ-LUC and 43 LUC plants were analyzed. LUC activity was determined by chemiluminescence assay using the activity of the purified protein as a standard.