Worm Breeder's Gazette 9(2): 91

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.

Effects of Duplicating X-Linked Genes on the General Expression of the X Chromosome

L. Casson and B. Meyer

mnDp10 is a large duplication of the right side of X, covering the 
myo-2 gene.  Northern assays indicate that an XX hermaphrodite 
carrying two copies of mnDp10 accumulates twice as much myo-2 mRNA as 
a wild-type hermaphrodite.  This observation indicates that expression 
of the myo-2 gene is in proportion to its copy number, an important 
control for our dosage compensation experiments.  In examining three 
other X-linked loci not covered by this duplication, we discovered 
that the two dosage compensated loci, uxt-1 (adjacent to sup-7) and 
uvt-4 (adjacent to the vit genes) are also affected by this 
duplication.  The levels of uxt-1 and uvt-4 mRNA are twice as high in 
the duplication strain as in a wildtype hermaphrodite strain.  However,
act-4 expression remains unchanged by mnDp10.  (Expression of uxt-1 
and uvt-4 is elevated in dpy-21, dpy27, dpy-28, and egl-16 strains 
whereas expression of act-4 is not).  We are currently investigating 
the relevance of these observations to the mechanism of dosage 
compensation.  (Phil Meneely has observed a similar phenomenon: lin-15 
hypomorphs are suppressed by X duplications not covering this locus.)