Submitted February 25, 2002
Returned for revision March 15, 2002
Accepted July 12, 2002
Embryo
Structure and Regulation of the Murine Mash2 Gene
Holger Stepan 1,
Wiebke Marqwardt 1,
Yvonne Kuhn 2,
Michael Höckel 1,
Heinz-Peter Schultheiss 3,
Thomas Walther 4*
1 University of Leipzig
2 Univesity of Leipzig
3 Free Univesity of Berlin
4 University Hospital Benjamin Franklin
* To whom correspondence should be addressed. E-mail: thomas.walther{at}ukbf.fu-berlin.de.
Abstract
Transcription factors of the basic helix-loop-helix family
like Mash2 are essential for adequate
differentiation of the trophoblast. Disruption of the
Mash2 gene leads to early intrauterine death due to
placental insufficiency with an absent spongiotrophoblast
and an underdeveloped chorion. The aim of this study was
to analyze the structure of the murine Mash2 gene,
to screen a broad spectrum of organs for its expression
and to investigate its placental Mash2 expression
at different gestational ages. The RNase protection assay
identified beside the postulated Mash2 mRNA two
unexpected Mash2 transcripts which could be
confirmed by an 5' RACE approach.
However, all three transcripts were detectable exclusively
in murine placenta and not in other organs like the ovary,
uterus, skin, lung, femur, skeletal muscle, kidney, skull,
adrenal gland, tongue, stomach, spleen, skin, testis, or
pancreas. Sequence analysis disclosed an additional
transcription start site upstream of exon 2. Placental
Mash2 mRNA is measurable at all investigated stages
of gestation. After its initial detection on day 8.5 p.c.
(set to 100%; 100.0 ± 28.4%), the
Mash2-mRNA concentration increases significantly
and reaches a maximum of 812.0 ± 69.7 % on day
12.5 p.c. The second half of gestation is marked by a more
than eight-fold Mash2 decrease by day 18.5 p.c.
(77.0 ± 28.4%). A 36.9 ± 4.7% level of
placental Mash2 mRNA is measurable at term.
Key words:
Embryo •
Pregnancy •
Placenta
