Diverse Genetic Regulatory Motifs Required for Murine Adenosine Deaminase Gene Expression in the Placenta

doi:10.1074/jbc.272.4.2334

Diverse Genetic Regulatory Motifs Required for Murine Adenosine Deaminase Gene Expression in the Placenta*

From the ^‡ Verna and Marrs McLean Department of Biochemistry and
** Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030

^‡‡ To whom correspondence should be addressed:
Dept. of Biochemistry, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
. Tel.: 713-798-4572; Fax: 713-796-9438; E-mail: rkellems{at}bcm.tmc.edu.

↵^¶ Current address: Dept. of Pediatrics, Baylor College of Medicine, Houston, TX 77030.

Abstract

Murine adenosine deaminase (ADA) is a ubiquitous purine catabolic enzyme whose expression is subject to developmental and tissue-specific regulation. ADA is enriched in trophoblast cells of the chorioallantoic placenta and is essential for embryonic and fetal development. To begin to understand the genetic pathway controlling Ada gene expression in the placenta, we have identified and characterized a 770-base pair fragment located 5.4 kilobase pairs upstream of the Ada transcription initiation site, which directs reporter gene expression to the placenta of transgenic mice. The expression pattern of the reporter gene reflected that of the endogenous Ada gene in the placenta. Sequence analysis revealed potential binding sites for bHLH and GATA transcription factors. DNase I footprinting defined three protein binding regions, one of which was placenta-specific. Mutations in the potential protein binding sites and footprinting regions resulted in loss of placental expression in transgenic mice. These findings indicate that multiple protein binding motifs are necessary for Ada expression in the placenta.

Footnotes

↵^§ Supported by Robert A. Welch Foundation Predoctoral Fellowship Q-893.
↵^| Supported by National Institutes of Health Postdoctoral Fellowship HD07843.
↵* This work was supported in part by National Institutes of Health Grant DK46207 and HD34130. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) U73185[GenBank].
↵¹ The abbreviations used are:

ADA

adenosine deaminase

dpc

days post coitum

CAT

chloramphenicol acetyltransferase

kb

kilobase pair(s)

bp

base pair(s)

TSE

trophoblast-specific element

TSEB

trophoblast-specific element-binding protein

bHLH

basic helix-loop-helix

hPL

human placental lactogen.
↵² D. Shi, unpublished observations.
↵³ P. Xu, unpublished observations.
- Received August 7, 1996.