shown to promote readthrough in vitro. Mutations 
within the Mo-MuLV spacer region have varied ef- 
fects on readthrough. 
These results imply a complex stimulator for 
readthrough that includes the downstream pseu- 
doknot and local sequence context near the UAG 
codon. Focus is currently on the importance of the 
conserved nucleotides in the second loop of the 
pseudoknot and on pseudoknot structural analyses. 
Pseudoknot function in Saccharomyces cerevisiae 
is being studied to initiate a genetic approach to 
identifying cellular components that interact with 
the pseudoknot to promote readthrough. 
DNA Sequencing Technology 
Multiplex sequencing technology coupled with a 
transposon-based front end is being given a serious 
pilot test on human DNA to assess the efficiency and 
the problems of scale-up. Direct readout of chemilu- 
minescent probes on the sequencing membranes 
with a CCD (charge-coupled device) camera is be- 
ing developed with the goal of building an auto- 
mated system. A sequence reading device has been 
developed and is being tested. 
In collaboration with the Computer Science De- 
partment at the University of Utah, custom chips 
have been fabricated that do very fast parallel se- 
quence comparisons. These are compatible with 
small computers and should greatly enhance the 
power of homology searches of the increasingly 
large DNA sequence database. Two technologies are 
being pushed for fast sequence comparisons of hu- 
man populations. 
Capillary technology is being developed for poly- 
merase chain reaction (PCR) -based rapid assays of 
variants, and a multiplex approach that does direct 
comparison of raw sequences to look for differences 
is in early development. 
The studies on sequencing technology are sup- 
ported by grants from the Department of Energy and 
the National Institutes of Health. 
Dr. Gesteland is also Professor of Human Genet- 
ics and of Biology at the University of Utah School 
of Medicine and Adjunct Professor of Bioengi- 
neering at the University of Utah. 
Articles 
Chu, T.J., Caldwell, K.D., Weiss, R., Gesteland, 
R.F., and Pitt, W.G. 1992. Low fluorescence 
background electroblotting membrane for DNA 
sequencing. Electrophoresis 13:105-114. 
Condron, B.G., Atkins, J.F., and Gesteland, R.F. 
1991. Frameshifting in gene 10 of bacteriophage 
T7 . f Bacteriol 173:6998-7003. 
Condron, B.G., Gesteland, R.F., and Atkins J.F. 
1 99 1 • An analysis of sequences stimulating frame- 
shifting in the decoding of gene 1 0 of bacterio- 
phage T7. Nucleic Acids Res 19:5607-5612. 
Karger, A.E., Harris, J.M., and Gesteland, R.F. 
1991. Multiwavelength fluorescence detection 
for DNA sequencing using capillary electrophore- 
sis. Nucleic Acids Res 19:4955-4962. 
Pagel, F.T., Tuohy, T.M.F., Atkins, J.F. , and Murgola, 
E.J. 1992. Doublet translocation at GGA is me- 
diated directly by mutant tRNAf / Bacterial 
174:4179-4182. 
Swerdlow, H., Zhang, J. Z., Chen, D.Y., Harke, H.R., 
Grey, R., Wu, S., Dovichi, N.J., and Fuller, C. 
1991. Three DNA sequencing methods using cap- 
illary gel electrophoresis and laser-induced fluo- 
rescence. Anal Chem 63:2835-2841. 
Weiss, R.B. 1991. Ribosomal frameshifting, jump- 
ing and readthrough. Curr Opin Cell Biol 
3:1051-1055. 
196 
