Worm Breeder's Gazette 8(2): 40

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.

Walking Away From the Yolk Protein Genes

U. Heine, and T. Blumenthal

In order to facilitate molecular analysis of the chromosomal domains 
in which the C.  elegans yolk protein genes are situated, we have 
cloned the surrounding DNA using the chromosome walking technique.  We 
have cloned at least 25 kb of DNA on each side of each yolk protein 
gene (> 230 kb total).  Preliminary analysis of this DNA allows the 
following tentative conclusions to be 
drawn:
1.  Walking, using J.  Karn's SG25 (Sau3a partial digest) genomic 
library, has not presented us with any difficulties.  All regions have 
been represented by overlapping clones.
2.  The cloned DNA contains only four examples of middle repetitive 
DNA.  The repeats appear to be small and to have a low copy number.  
They are not associated with detectable transcripts.
3.  Seven regions transcribed in adult hermaphrodites, in addition 
to the five yolk protein genes, have been detected so far in the 
cloned DNA.  The RNAs from all of these genes are present at levels 
less than 10% of the yolk protein mRNAs.  (Very low abundance 
transcripts would not have been detected.) The walk has not yet been 
analyzed for the presence of genes transcribed in larvae or males.
4.  Two Bristol/Bergerac polymorphisms have been found: A Tc1 
between YP3 and YP4 allowed mapping of these genes to the X chromosome.
A second 1.6 kb insertion about 30 kb to the right of YP1 has been 
detected in the Bergerac chromosome.
5.  Except for the YP3 and YP4 genes, originally found on a single 
clone, the yolk protein genes are not clustered.