Abstract
Spermatogenesis is a complex process requiring the coordinate expression of a number of testis-specific genes. One of these, Pdha-2, codes for the murine spermatogenesis-specific isoform of the E1a subunit of the pyruvate dehydrogenase complex. To begin to delineate the mechanisms regulating its expression in vivo, we have generated transgenic mice lines carrying Pdha-2 promoter deletion constructs. Here we report that transgenic mice harboring a construct containing only 187 bp of promoter and upstream sequences (core promoter) is sufficient for directing the testis-specific expression of a chloramphenicol acetyltransferase (CAT) reporter gene. Like the endogenous Pdha-2, the CAT gene is expressed in testis in a stage-specific manner. Our studies also show a correlation between CpG methylation within the core promoter and its capacity to regulate transcription. In NIH 3T3 cell lines stably transfected with the Pdha-2 core promoter-CAT construct, high levels of CAT reporter expression are observed, whereas the endogenous Pdha-2 gene is repressed. In these cells, the CpG dinucleotides residing within the transfected promoter are hypomethylated whereas those residing in the endogenous promoter are methylated. Furthermore, promoter activity can be abated by the in vitro methylation of its CpG dinucleotides. DNase I footprint analysis indicates that at least one site for the methylation-mediated repression may occur through the ATF/cyclic AMP response element binding element located within the core promoter. Mutations within this element reduces activity to approximately 50% of the wild-type promoter activity. These results suggest that tissue-specific gene expression may be modulated by other mechanisms in addition to specific transcription factor availability and cooperativity. We propose that methylation may be a mechanism by which repression of the testis-specific Pdha-2 gene is established in somatic tissue.
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- Ariel M., Cedar H., McCarrey J. Developmental changes in methylation of spermatogenesis-specific genes include reprogramming in the epididymis. Nat Genet. 1994 May;7(1):59–63. doi: 10.1038/ng0594-59. [DOI] [PubMed] [Google Scholar]
- Ariel M., McCarrey J., Cedar H. Methylation patterns of testis-specific genes. Proc Natl Acad Sci U S A. 1991 Mar 15;88(6):2317–2321. doi: 10.1073/pnas.88.6.2317. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brown R. M., Dahl H. H., Brown G. K. Pyruvate dehydrogenase E1 alpha subunit genes in the mouse: mapping and comparison with human homologs. Somat Cell Mol Genet. 1990 Sep;16(5):487–492. doi: 10.1007/BF01233198. [DOI] [PubMed] [Google Scholar]
- Brown R. M., Dahl H. H., Brown G. K. X-chromosome localization of the functional gene for the E1 alpha subunit of the human pyruvate dehydrogenase complex. Genomics. 1989 Feb;4(2):174–181. doi: 10.1016/0888-7543(89)90297-8. [DOI] [PubMed] [Google Scholar]
- Bucci L. R., Brock W. A., Johnson T. S., Meistrich M. L. Isolation and biochemical studies of enriched populations of spermatogonia and early primary spermatocytes from rat testes. Biol Reprod. 1986 Feb;34(1):195–206. doi: 10.1095/biolreprod34.1.195. [DOI] [PubMed] [Google Scholar]
- Bunick D., Johnson P. A., Johnson T. R., Hecht N. B. Transcription of the testis-specific mouse protamine 2 gene in a homologous in vitro transcription system. Proc Natl Acad Sci U S A. 1990 Feb;87(3):891–895. doi: 10.1073/pnas.87.3.891. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Choi Y. C., Chae C. B. DNA hypomethylation and germ cell-specific expression of testis-specific H2B histone gene. J Biol Chem. 1991 Oct 25;266(30):20504–20511. [PubMed] [Google Scholar]
- Chomczynski P., Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987 Apr;162(1):156–159. doi: 10.1006/abio.1987.9999. [DOI] [PubMed] [Google Scholar]
- Dahl H. H., Brown R. M., Hutchison W. M., Maragos C., Brown G. K. A testis-specific form of the human pyruvate dehydrogenase E1 alpha subunit is coded for by an intronless gene on chromosome 4. Genomics. 1990 Oct;8(2):225–232. doi: 10.1016/0888-7543(90)90275-y. [DOI] [PubMed] [Google Scholar]
- Foulkes N. S., Mellström B., Benusiglio E., Sassone-Corsi P. Developmental switch of CREM function during spermatogenesis: from antagonist to activator. Nature. 1992 Jan 2;355(6355):80–84. doi: 10.1038/355080a0. [DOI] [PubMed] [Google Scholar]
- Frommer M., McDonald L. E., Millar D. S., Collis C. M., Watt F., Grigg G. W., Molloy P. L., Paul C. L. A genomic sequencing protocol that yields a positive display of 5-methylcytosine residues in individual DNA strands. Proc Natl Acad Sci U S A. 1992 Mar 1;89(5):1827–1831. doi: 10.1073/pnas.89.5.1827. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gebara M. M., McCarrey J. R. Protein-DNA interactions associated with the onset of testis-specific expression of the mammalian Pgk-2 gene. Mol Cell Biol. 1992 Apr;12(4):1422–1431. doi: 10.1128/mcb.12.4.1422. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goldsborough A., Ashworth A., Willison K. Cloning and sequencing of POU-boxes expressed in mouse testis. Nucleic Acids Res. 1990 Mar 25;18(6):1634–1634. doi: 10.1093/nar/18.6.1634. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gorman C. M., Moffat L. F., Howard B. H. Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells. Mol Cell Biol. 1982 Sep;2(9):1044–1051. doi: 10.1128/mcb.2.9.1044. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goto M., Tamura T., Mikoshiba K., Masamune Y., Nakanishi Y. Transcription inhibition of the somatic-type phosphoglycerate kinase 1 gene in vitro by a testis-specific factor that recognizes a sequence similar to the binding site for Ets oncoproteins. Nucleic Acids Res. 1991 Jul 25;19(14):3959–3963. doi: 10.1093/nar/19.14.3959. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grimes S. R., Wolfe S. A., Koppel D. A. Tissue-specific binding of testis nuclear proteins to a sequence element within the promoter of the testis-specific histone H1t gene. Arch Biochem Biophys. 1992 Aug 1;296(2):402–409. doi: 10.1016/0003-9861(92)90590-s. [DOI] [PubMed] [Google Scholar]
- Gruenbaum Y., Cedar H., Razin A. Substrate and sequence specificity of a eukaryotic DNA methylase. Nature. 1982 Feb 18;295(5850):620–622. doi: 10.1038/295620a0. [DOI] [PubMed] [Google Scholar]
- Iannello R. C. DNase I footprinting using PCR-generated end-labeled DNA probes. Methods Mol Biol. 1995;37:379–391. doi: 10.1385/0-89603-288-4:379. [DOI] [PubMed] [Google Scholar]
- Iannello R. C., Dahl H. H. Transcriptional expression of a testis-specific variant of the mouse pyruvate dehydrogenase E1 alpha subunit. Biol Reprod. 1992 Jul;47(1):48–58. doi: 10.1095/biolreprod47.1.48. [DOI] [PubMed] [Google Scholar]
- Iannello R. C., Kola I., Dahl H. H. Temporal and tissue-specific interactions involving novel transcription factors and the proximal promoter of the mouse Pdha-2 gene. J Biol Chem. 1993 Oct 25;268(30):22581–22590. [PubMed] [Google Scholar]
- Johnson P. A., Bunick D., Hecht N. B. Protein binding regions in the mouse and rat protamine-2 genes. Biol Reprod. 1991 Jan;44(1):127–134. doi: 10.1095/biolreprod44.1.127. [DOI] [PubMed] [Google Scholar]
- Lim K., Chae C. B. Presence of a repressor protein for testis-specific H2B (TH2B) histone gene in early stages of spermatogenesis. J Biol Chem. 1992 Aug 5;267(22):15271–15273. [PubMed] [Google Scholar]
- Maragos C., Hutchison W. M., Hayasaka K., Brown G. K., Dahl H. H. Structural organization of the gene for the E1 alpha subunit of the human pyruvate dehydrogenase complex. J Biol Chem. 1989 Jul 25;264(21):12294–12298. [PubMed] [Google Scholar]
- Nayernia K., Burkhardt E., Beimesche S., Keime S., Engel W. Germ cell-specific expression of a proacrosin-CAT fusion gene in transgenic mouse testis. Mol Reprod Dev. 1992 Apr;31(4):241–248. doi: 10.1002/mrd.1080310403. [DOI] [PubMed] [Google Scholar]
- Nelki D., Dudley K., Cunningham P., Akhavan M. Cloning and sequencing of a zinc finger cDNA expressed in mouse testis. Nucleic Acids Res. 1990 Jun 25;18(12):3655–3655. doi: 10.1093/nar/18.12.3655. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ngô V. M., Laverrière J. N., Gourdji D. CpG methylation represses the activity of the rat prolactin promoter in rat GH3 pituitary cell lines. Mol Cell Endocrinol. 1995 Feb 27;108(1-2):95–105. doi: 10.1016/0303-7207(94)03462-3. [DOI] [PubMed] [Google Scholar]
- Peschon J. J., Behringer R. R., Brinster R. L., Palmiter R. D. Spermatid-specific expression of protamine 1 in transgenic mice. Proc Natl Acad Sci U S A. 1987 Aug;84(15):5316–5319. doi: 10.1073/pnas.84.15.5316. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Robinson M. O., McCarrey J. R., Simon M. I. Transcriptional regulatory regions of testis-specific PGK2 defined in transgenic mice. Proc Natl Acad Sci U S A. 1989 Nov;86(21):8437–8441. doi: 10.1073/pnas.86.21.8437. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Romrell L. J., Bellvé A. R., Fawcett D. W. Separation of mouse spermatogenic cells by sedimentation velocity. A morphological characterization. Dev Biol. 1976 Mar;49(1):119–131. doi: 10.1016/0012-1606(76)90262-1. [DOI] [PubMed] [Google Scholar]
- Stewart T. A., Hecht N. B., Hollingshead P. G., Johnson P. A., Leong J. A., Pitts S. L. Haploid-specific transcription of protamine-myc and protamine-T-antigen fusion genes in transgenic mice. Mol Cell Biol. 1988 Apr;8(4):1748–1755. doi: 10.1128/mcb.8.4.1748. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Takakubo F., Dahl H. H. The expression pattern of the pyruvate dehydrogenase E1 alpha subunit genes during spermatogenesis in adult mouse. Exp Cell Res. 1992 Mar;199(1):39–49. doi: 10.1016/0014-4827(92)90459-l. [DOI] [PubMed] [Google Scholar]
- Tamura T., Makino Y., Mikoshiba K., Muramatsu M. Demonstration of a testis-specific trans-acting factor Tet-1 in vitro that binds to the promoter of the mouse protamine 1 gene. J Biol Chem. 1992 Mar 5;267(7):4327–4332. [PubMed] [Google Scholar]
- Tymms M. J. Quantitative measurement of mRNA using the RNase protection assay. Methods Mol Biol. 1995;37:31–46. doi: 10.1385/0-89603-288-4:31. [DOI] [PubMed] [Google Scholar]
- Widen S. G., Wilson S. H. Mammalian beta-polymerase promoter: large-scale purification and properties of ATF/CREB palindrome binding protein from bovine testes. Biochemistry. 1991 Jun 25;30(25):6296–6305. doi: 10.1021/bi00239a031. [DOI] [PubMed] [Google Scholar]