Submitted to: Journal of Nutritional Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2004
Publication Date: November 1, 2004
Citation: Zeng, H., Saari, J.T. 2004. Increased type I collagen content and DNA binding activity of a single-stranded, cytosine-rich sequence in the high-salt buffer protein extract of the copper-deficient rat heart. Journal of Nutritional Biochemistry. 15:694-99. Interpretive Summary: Dietary Cu-deficiency not only causes a hypertrophic cardiomyopathy but also increases the cancer risk in rodent models. However, possible alteration in the program of gene expression has not been fully examined. It is important to understand the effect of dietary copper deficiency on this process which may lead to the development of sensitive biological indicators related to copper status in humans and the identification of new function related to the role of copper in heart. The present data demonstrate that Cu adequacy is not only necessary for the synthesis and deposition of type I collagen but also appears to be necessary for maintaining DNA integrity. These findings will be useful for scientists and health-care people who are interested in understanding the importance of dietary copper in heart function and cancer risk.
Technical Abstract: Dietary Cu-deficiency not only causes a hypertrophic cardiomyopathy but also increases cancer risk in rodent models. However, a possible alteration in gene expression has not been fully examined. The present study was undertaken to determine the effect of Cu-deficiency on protein profiles in rat heart tissue. Male Sprague-Dawley rats were fed diets that were either copper adequate (6.0 ug copper/g diet n=6) or copper deficient (0.3 ug copper/g diet n=6) for 5 wk. Nuclear extracts from heart tissue of Cu-deficient, but not Cu-adequate rats showed a 132 kDa protein complex by SDS-PAGE analysis. This complex stained pink with Coomassie Blue, suggesting the presence of collagens or other proline-rich proteins. Dot immunoblotting demonstrated that total type I collagen was increased by 110% in the nuclear extract from Cu-deficient, relative to Cu-adequate animals. Liquid chromatography mass spectrometry analysis indicated that the 132 kDa protein complex contained a collagen alpha (I) chain precursor as well as a leucine-rich protein 130 in the nuclear extract from Cu-deficient, but not Cu-adequate rats. A gel shift assay showed that nuclear extract from Cu-deficient rats bound to a single-stranded cytosine-rich sequence with higher affinity than the extract of Cu-adequate rats, similar to reports of an increase in DNA binding activity of a single-stranded cytosine-rich sequence in several types of tumor cells. The present data demonstrate that Cu adequacy is not only necessary for the synthesis and deposition of type I collagen but also appears to be necessary for maintaining genome DNA integrity.