Expression of a mouse Zfy-1/lacZ transgene in the somatic cells of the embryonic gonad and germ cells of the adult testis.
The Zfy-1 and Zfy-2 genes, which arose by gene duplication, map to the mouse Y chromosome and encode nearly identical zinc-finger proteins. Zfy-1 is expressed in the genital ridge and adult testis and likely encodes a transcription activator. Although potential roles in sex determination and spermatogenesis have been hotly debated, the biological functions of Zfy-1 remain unknown. To study the gene's regulation, transgenes with 21-28 kb of Zfy-1 5' flanking DNA placed upstream of lacZ were constructed in plasmids or created by homologous recombination of coinjected DNA molecules. The resulting transgenic mice expressed beta-galactosidase in the genital ridge of both males and females starting between embryonic day 10 and 11 (E10-E11), peaking at E12-E13 and then declining to low levels by E15, a pattern that matches Zfy-1 mRNA as detected by RT-PCR. This lacZ expression in genital ridge was confined to somatic cells as demonstrated by its absence from the alkaline phosphatase-positive germ cells. It had been reported previously that Zfy-1 mRNA was absent from the embryonic gonad of homozygous W(e) embryos, which virtually lack germ cells. By contrast, we observed normal expression of the Zfy-1/lacZ transgene when introduced into the W(e) background, suggesting that germ cells are not necessary for expression. In the adult, the Zfy-1/lacZ transgene is expressed abundantly in developing germ cells. Extragonadal (kidney, meninges, arteries, choroid plexus) expression of the transgene was also observed in embryos. A smaller transgene with only 4.3 kb of Zfy-1 5' flanking DNA was expressed only in germ cells of adult mice. These results suggest that an enhancer for germ cell expression in the adult lies near the Zfy-1 promoter and that an enhancer for expression in the somatic cells of the embryonic gonad is located further 5'.
Zambrowicz
B P
BP
Howard Hughes Medical Institute, University of Washington SL-15, Seattle 98195.
Zimmermann
J W
JW
Harendza
C J
CJ
Simpson
E M
EM
Page
D C
DC
Brinster
R L
RL
Palmiter
R D
RD
D000469:Alkaline Phosphatase; D000818:Animals; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D015870:Gene Expression / Q000502:physiology; D005854:Germ Cells / Q000502:physiology*; D007763:Lac Operon / Q000235:genetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic / Q000196:embryology / Q000235:genetics*; D013737:Testis / Q000196:embryology*; D014157:Transcription Factors; D014998:Y Chromosome; D016335:Zinc Fingers / Q000235:genetics*; D001616:beta-Galactosidase
D004268:DNA-Binding Proteins; D014157:Transcription Factors; C501342:Zfy1 protein, mouse; C501343:Zfy2 protein, mouse; D000469:Alkaline Phosphatase; D001616:beta-Galactosidase