Differential Appearance of DNase I-hypersensitive Sites Correlates with Differential Transcription of Pgk Genes during Spermatogenesis in the Mouse*
- From the Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, Texas 78245
- ‡ To whom correspondence should be addressed: Dept. of Genetics, Southwest Foundation for Biomedical Research, P. O. Box 760549, San Antonio, TX 78245. Tel.: 210-670-3232; Fax: 210-670-3316; E-mail: johnmc{at}darwin.sfbr.org
Abstract
Two functional genes encoding phosphoglycerate kinase are differentially expressed during spermatogenesis in the mouse. Expression of the X-linked Pgk-1 gene is repressed coincident with X chromosome inactivation during prophase of meiosis I. At this same stage, expression of the autosomal Pgk-2 gene is initiated by tissue-specific mechanisms. To investigate the role of chromatin structure in these processes, we have examined the appearance and disappearance of DNase I-hypersensitive (DH) sites in each gene, and correlated this with transcriptional activity as measured by nuclear run-off analysis at specific stages of spermatogenesis. Our results demonstrate that the occurrence of DH sites is related to periods of active transcription. Results with the Pgk-1 gene indicate that transcriptional inactivation of the X chromosome in spermatogenic cells may not be as complete as that in somatic cells, and that maximum repression may be limited to a very transient period during the pachytene stage of first meiotic prophase. Results with the Pgk-2 gene indicate that DH sites appear coincident with, or just prior to, transcriptional activation of this gene. The implications of these results are discussed with respect to the role of X chromosome inactivation in spermatogenic cells and the developmental order of molecular events that regulate differential gene expression during spermatogenesis.
Footnotes
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↵* This work was supported in part by National Institutes of Health Grant HD 23126 and National Science Foundation Grant DMB-9305858. 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.
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↵1 The abbreviations used are:
- PGK
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phosphoglycerate kinase
- DH
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DNase I-hypersensitive
- XCI
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X chromosome inactivation
- TES
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N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid
- kb
-
kilobase pair(s).
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↵2 P. Burgoyne, personal communication.
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- Received February 26, 1996.
- Revision received April 4, 1996.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
