A. Nagy et al., DISSECTING THE ROLE OF N-MYC IN DEVELOPMENT USING A SINGLE TARGETING VECTOR TO GENERATE A SERIES OF ALLELES, Current biology, 8(11), 1998, pp. 661-664
The N-myc proto-oncogene is expressed in many organs of the mouse embr
yo, suggesting that it has multiple functions. A null mutation leads t
o mid-gestation lethality [1-4], obscuring the later roles of the gene
in organogenesis. We have generated a multi-purpose gene alteration b
y combining the potential for homologous and site-specific recombinati
on in a single targeting vector, and using the selectable marker for n
eomycin-resistance, neo, to downregulate gene activity. This allowed u
s to create a series of alleles that led to different levels of N-myc
expression. The phenotypes revealed a spectrum of developmental proble
ms. The hypomorphic allele produced can be repaired in situ by Cre-rec
ombinase-mediated DNA excision. We show here for the first time the us
e of a single targeting vector to generate an allelic series. This, an
d the possibility of subsequent lineage-specific or conditional allele
repair in situ, represent new genome modification strategies that can
be used to investigate multiple functions of a single gene, (C) Curre
nt Biology Ltd ISSN 0960-9822.