This work centers on the high molecular weight, high mobility group (HMG), nonhistone chromatin proteins. We have found that in cultures of rapidly proliferating cells HMG-17 requires much higher NaCL concentrations for dissociation from chromatin than is required for its dissociation from chromatin of quiescent cells. This suggests a possible involvement of this protein in DNA replication. We have shown that HMG-1 and HMG-2 occur in cultured hepatoma cells in much higher amounts than in adult rat liver and that both proteins possess preferential affinity for single-stranded DNA. We discovered a three-domain organization of HMG-1 and HMG-2. Two of the domains are sequence homologous, globular, DNA-binding domains. The third domain is probably a random coil that binds to histones. The proteins are thus peculiarly adapted to interact through separate domains with both DNA and histones. We have searched for nonhistone chromosomal proteins that bind to single-stranded DNA in the presence of dextran sulfate. This polyanionic reagent has been suggested by other workers to dissociate proteins that bind nonspecifically to single-stranded DNA. Dextran sulfate-resistant proteins, several of which we have now identified in cultured L cells and none of which are HMG proteins, are presumed to have a more specific interaction with single-stranded DNA and are more likely to interact with single-stranded DNA in vivo. Ion-exchange HPLC appears to offer a suitable method for fractionating the dextran sulfate-resistant fraction to obtain individual, purified proteins for intensive study. (K)

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
2R01CA017782-10
Application #
3164787
Study Section
Pathobiochemistry Study Section (PBC)
Project Start
1978-07-01
Project End
1989-12-31
Budget Start
1985-01-01
Budget End
1985-12-31
Support Year
10
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Kansas State University
Department
Type
Schools of Arts and Sciences
DUNS #
City
Manhattan
State
KS
Country
United States
Zip Code
66506
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Wen, L; Huang, J K; Blackshear, P J (1989) Rat ornithine decarboxylase gene. Nucleotide sequence, potential regulatory elements, and comparison to the mouse gene. J Biol Chem 264:9016-21
Wen, L; Huang, J K; Johnson, B H et al. (1989) A human placental cDNA clone that encodes nonhistone chromosomal protein HMG-1. Nucleic Acids Res 17:1197-214
Abdul-Razzak, K K; Denton, M L; Cox, D J et al. (1989) Isolation and characterization of folded fragments released by Staphylococcal aureus proteinase from the non-histone chromosomal protein HMG-1. Biochim Biophys Acta 996:125-31
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