Showing papers by "Hui Zhang published in 1994"

p21-containing cyclin kinases exist in both active and inactive states.

Abstract: In normal fibroblasts CDKs exist predominantly in p21/PCNA/cyclin/CDK quaternary complexes, whereas in p53-deficient cells, p21 expression is depressed and the kinases are reduced to a cyclin/CDK binary state. p21 is a universal cyclin kinase inhibitor, but we show here that p21-containing complexes exist in both catalytically active and inactive forms. This finding challenges the current view that active cyclin kinases function only in the binary state and reveals the subtlety with which tumor-suppressor proteins modulate the cell cycle.

Chromosomal mapping of human CDK2, CDK4, and CDK5 cell cycle kinase genes

Abstract: Cyclin dependent kinases (CDK's) are kinases that interact with cyclins and regulate cell division. Genomic clones encoding human CDK2, CDK4, and CDK5 were obtained and mapped to their respective chromosomal loci using fluorescence in situ hybridization on human lymphocyte metaphase spreads. Interestingly, CDK2 and CDK4 were located at the same position, 12q13, and CDK5 was mapped to 7q36. 12q13 has been shown to be associated with chromosome alterations such as amplifications and translocations in solid tumors. 7q36 does not appear to be a major site of chromosome alterations in tumors. As CDK2 and CDK4 appear to be important in regulating the human cell cycle, it is possible that the alterations of the 12q13 locus in tumors may involve changes in the regulation of CDK2 and CDK4 genes.