On feb. 7 1996 Cris Somerville wrote that due to a sequencing error, the GUS fusion in the AtLTP1-GUS
fusion (described in Thoma et al., Plant Physiology, (1994) 105: 35-45) was made downstream AND
OUT OF FRAME with the normal start-site of translation (as noticed by Cathie Martin).
In fact, an additional C has to be introduced at position 1276 in the sequence given in Figure 2 of Thoma
et al. This results in
a new ATG at position 1214. As a consequence, the first 13 amino-acids given in Figure 1 and Figure 2
(MLALGLHDCGRSN) are not correct. They should be replaced by MAGVMKLACLLLACMIVAGPI . After
these, the a.a. sequence (starting with TSNAAL.....) is correct. This results in a much higher homology of
the N-terminal part of the Arabidopsis protein to the Spinach protein than suggested in Figure 1.
The GUS fusion includes LTP1 promoter sequence upto nucleotide 1227, thus including the ATG and 1
nucleotide of the LTP1 gene. HOWEVER, IN THE PROMOTER-GUS FUSION, THE ATG OF THE LTP1 GENE
AND THE ATG OF THE GUS GENE OF PBI101 ARE IN FRAME.
Therefore, the only effect is the N-terminal fusion of 9 amino acids to the GUS-protein, which is unlikely
to be the cause of Artifactual GUS-staining.
Marcel Toonen in our lab cloned the LTP1 promoter sequence described above in front of a promoterless
luciferase coding sequence using the same restriction sites as used for the LTP1-GUS construct. The
LTP1 promoter drives expression of the luciferase gene in transgenic carrot cell clusters, somatic
embryos and the cotyledons of plantlets, confirming in situ data and the LTP1-GUS pattern in
Sacco de Vries Lab
Dept. of Molecular Biology
Wageningen Agricultural University
Casper.Vroemen at mac.mb.wau.nl