Differential expression of myc family genes during murine development.
The myc family of cellular oncogenes contains three known members. The N-myc and c-myc genes have 5'-noncoding exons, strikingly homologous coding regions, and display similar oncogenic potential in an in vitro transformation assay. The L-myc gene is less well characterized, but shows homology to N-myc and c-myc (ref. 6; also see below). c-myc is expressed in most dividing cells, and deregulated expression of this gene has been implicated in the development of many classes of tumours. In contrast, expression of N-myc has been found only in a restricted set of tumours, most of which show neural characteristics; these include human neuroblastoma, retinoblastoma and small cell lung carcinoma (SCLC). L-myc expression has so far been found only in SCLC. Activated N-myc and L-myc expression has been implicated in oncogenesis; for example, although N-myc expression has been found in all neuroblastomas tested, activated (greatly increased) N-myc expression, resulting from gene amplification, is correlated with progression of the tumour. We now report that high-level expression of N- and L-myc is very restricted with respect to tissue and stage in the developing mouse, while that of c-myc is more generalized. Furthermore, we demonstrate that N-myc is not simply a neuroectoderm-specific gene; both N- and L-myc seem to be involved in the early stages of multiple differentiation pathways. Our findings suggest that differential myc gene expression has a role in mammalian development and that the normal expression patterns of these genes generally predict the types of tumours in which they are expressed or activated.
K A
KA
Zimmerman
G D
GD
Yancopoulos
R G
RG
Collum
R K
RK
Smith
N E
NE
Kohl
K A
KA
Denis
M M
MM
Nau
O N
ON
Witte
D
D
Toran-Allerand
C E
CE
Gee
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology; D001483:Base Sequence; D002454:Cell Differentiation; D002460:Cell Line; D005786:Gene Expression Regulation; D009052:Leukemia Virus, Murine; D051379:Mice / Q000235:genetics* / Q000254:growth & development; D009857:Oncogenes; D010954:Plasmacytoma / Q000235:genetics; D012313:RNA / Q000032:analysis; D014018:Tissue Distribution
D012313:RNA