Characterization of Deoxyribonucleic Acid Sequences at the 5�� and 3�� Borders of the 100 Kilobase Pair Ovalbumin Gene Domain
Journal
Biochemistry
Journal Volume
22
Journal Issue
2
Pages
306-315
Date Issued
1983
Author(s)
Abstract
The ovalbumin and the ovalbumin-related X and Y genes are coordinately expressed in the chicken oviduct and are linked within a 100 kilobase pair (kbp) chromosomal domain of DNA which is preferentially sensitive to DNase I [Lawson, G. M., Knoll, B. J., March, C. J., Woo, S. L. C., Tsai, M.-J., & O'Malley, B. W. (1982) J. Biol. Chem. 257, 1501–1507; Lawson, G. M., Tsai, M.-J., & O'Malley, B. W. (1980) Biochemistry 19, 4403–4411]. At each end of this domain, the chromatin undergoes a structural transition such that the DNA becomes relatively more resistant to DNase I. In order to understand the mechanisms underlying this structural transition, we have been studying the characteristics of DNA sequences which are found at the 5′ and 3′ borders of the domain. We have discovered that members of a dispersed repetitive DNA sequence family (termed the CR1 family) are located near or within the transition regions of DNase I sensitivity; in addition, the CR1 sequences found at opposite ends of the domain exist in inverse orientations with respect to each other. These observations suggest that the CR1 sequences may possibly play a role in defining the ends of the ovalbumin gene DNase I sensitive domain. A consensus CR1 sequence is presented on the basis of a comparison of four homologous genomic sequences which are members of the CR1 family. We also searched for, but failed to obtain, any evidence that specific DNA rearrangements are involved in the expression of the ovalbumin gene. However, a region at the far 3′ end of the domain, approximately 30 kbp downstream from the ovalbumin gene, is highly enriched for HpaII/MspI restriction sites compared to most regions of the chicken genome. More importantly, this same region exhibits a pattern of methylation which is highly variable from one chicken tissue to another. In particular, DNA in the oviduct is specifically undermethylated in this region when compared to other tissues. Thus, this DNA at the 3′ border may serve as a control region involved in determining the structural state of the chromatin domain in which the ovalbumin gene family resides. © 1983, American Chemical Society. All rights reserved.
Type
journal article