Worm Breeder's Gazette 9(1): 24

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.

Attempts to Clone the Genes for the Dense-Body Proteins p107a and p107b

R. Barstead and R. Waterston

The muscle dense-bodies are functionally analogous to the Z-line in 
vertebrate skeletal muscle.  Two proteins in the dense-bodies, p107a 
and p1O7b, have been identified immunocytochemically, (Francis and 
Waterston, (1985) J.  Cell Biol.  81:in press).  The minimum length of 
sequence necessary to encode p1O7a and p1O7b is 2800 bp.  Given this 
size, there should be approximately 360 recombinants in our genomic 
DNA expression library which have a breakpoint within this sequence.  (
This calculation assumes that there is a break, on average, at every 8 
bp, which is in turn calculated from the number of recombinants in the 
initial library pool, 1X10+E7, and the haploid genome size, 8X10+E7).  
One sixth of these should be in-frame and in the proper orientation.  
In a screen of 1.5X10+E6 phage with an antiserum which recognizes both 
p1O7a and p1O7b, we recovered six positives.  If there are two genes 
this is half of the expected number, but we aren't too worried.
The sizes of the inserts in the putative dense-body clones range 
between 600 and 2200 bp.  Five of the clones produce a detectable  -
galactosidase fusion protein as judged by reaction with an anti- -
galactosidase serum.  In one of these five, the peptide which binds to 
anti- -galactosidase does not react with the anti-dense-body serum; 
however, the anti-dense-body serum does react with a peptide of a 
lower molecular weight.  A possible explanation is that the insert 
contains a transcriptional or translational start which is recognized 
by E.  coli.Finally, although we wish the rumors were true, we do not 
have a cDNA library; we are, however, working on it.