119 

 expected size of the plasmid was 5 kB (2 kB insert plus 

 about 3 kB for pBluescript) . Although the size cannot be 

 quantitated from this gel, it suggested that the DNA of the 

 various samples were of different sizes and that the three 

 DNA samples (SP3, SP5 and SP6) were identical in size (Fig. 

 7-1) . 



PAT and ADH cDNA. The tobacco cDNA library was 

 prepared similarly as above to clone cDNA encoding PAT or 

 ADH by using the specific antibody probe for each. About 

 twelve possible clones for each were removed from plates and 

 plaque purified. Several of the plasmids containing cDNAs 

 appear to be of an acceptable size (Fig. 7-1, although not 

 quantitatively determined) . The expected size of cDNA 

 encoding PAT is about 3 kB, based on a previous molecular- 

 weight estimation of 88,000 D (7) . A preliminary M^ 

 estimation of about 130,000 for ADH by gel chromatography in 

 N. silvestris (unpublished data, Bonner and Jensen, 1986) 

 suggests that cDNA encoding ADH might be about 2.1 kB if the 

 plant protein is a dimer (dimers from 57,600 up to 158,000 D 

 have been described in bacteria (46, 56) . Figure 7-1 shows 

 the plasmid DNA containing possible clones. 

 Functional complementation 



Both aroD (DQT") and aroE (SDH') mutants transformed 

 with SP3, SP5 or SP6 yielded transf ormants which grew on M9 

 medium without addition of aromatic amino acids. This 

 result was a strong indication that all three cDNA clones 



^ 



