Worm Breeder's Gazette 6(1): 31

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.

Cloning Tissue-Specific Genes

M. Lauth, P. Meneely, R. Knowlton

To study gene expression in embryogenesis, we are isolating clones 
of C.  elegans genes that appear to be regulated in development (WBG 5,
#1).  We especially want to identify genes that are tissue-specific 
in their expression.  We can obtain such clones by differential plaque 
hybridization, selecting cloned DNAs that hybridize to RNA from one 
tissue but not from others.  Our plan is to use RNA from dissected 
tissues of Ascaris, on the assumption that tissue-specific gene 
products in Ascaris will also be tissue-specific in C.  elegans.
Hybridizations are carried out under less stringent conditions than 
used with homologous DNAs, such that 40% of C.  elegans DNA can be 
driven to associate with Ascaris germ line DNA, while E.  coli DNA is 
still unreactive.  Radioactive cDNA probes are copied from poly-A RNAs 
from Ascaris intestine, muscle (with some nerve and hypodermis), ovary 
and precleavage egg.  Complementary sequences in the C.  elegans 
Charon clone library are detected by plaque hybridization on 
nitrocellulose filters.  Some cloned DNAs hybridize to all four cDNAs, 
but others are tissue-specific, giving positive responses with cDNA 
from only one or two tissues.
So far we have isolated about twenty clones that reproducibly 
hybridize to transcripts in only one or two of the four dissected 
tissues.  As expected, all these DNAs also hybridize to cDNA copied 
from C.  elegans RNA.  We now want to find out whether the expression 
of these genes is restricted to certain tissues in C.  elegans, and 
when the transcripts arise during development.