Worm Breeder's Gazette 8(3): 89

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

A Proposal for Cloning Genes by Tc-1 Tagging of mRNA

G. Benian, D. Moerman, R. Waterston

In the course of our studies on unc-22 mRNA (see elsewhere in this 
issue) we made an unexpected observation--Tc1 can be incorporated into 
a full length relatively stable transcript.  This in turn has 
suggested a potentially powerful method for recovering DNA from genes 
suffering Tc1 insertions.
In studies of the mRNA from the strain RW7012, which contains unc-22(
st136::Tc1) in a largely Bristol background, we found by Northern 
analysis that unc-22 hybridizing sequences were present at near normal 
levels but at a slightly lower mobility than the comparable wild type 
band.  A similar Northern probed with Tc1 reveals the same band in 
RW7012 but does not hybridize to any comparable band in N2.  
Apparently the Tc1 is incorporated at least in part into the unc-22 
message and accounts for the change in mobility.  The relative 
stability of the composite message is curious and at this point 
If this feature proves to be a frequent property of Tc1 induced 
alleles, it may be possible to use this feature to provide a short cut 
to cloning a gene.  In the Northern of RW7012 RNA, only the unc-22 
transcript gave a strong signal with the Tc1 probe.  Using Tc1 as a 
primer against total or size fractionated RNA one could generate cDNA 
to the 5' side of the Tc1, which could in turn be used to identify 
cloned sequences in an appropriate library.
We are currently trying to determine the generality of our findings 
by examining RNAs from various Tc1 induced alleles of unc-22 and other 
genes.  The report by Levis, et al., (Cell 38:471, 1984) that P can be 
incorporated into a larger reasonably stable white composite message 
in Drosophila gives us hope that a reasonable number of Tc1 induced 
alleles will display read-through transcription of Tc1.