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Characterization of a second human cyclin A that is highly expressed in testis and in several leukemic cell lines.

In this study, we isolated and characterized a human cyclin A-like gene that we named cyclin A1. Cyclin A1 has 48% identity with human cyclin A and is more related to the recently cloned murine cyclin A1 (84% identity). The human cyclin A1 is specifically expressed in testis and brain among all of the normal tissues that we studied by Northern blot analysis; in addition, it is expressed in several myeloid leukemia cell lines, including ML-1, U937, NB4, KG-1, and THP1. A sensitive reverse transcription-PCR-Southern blot method also detected low-level expression of this gene in many other hematopoietic and nonhematopoietic cell lines. The expression of cyclin A1 mRNA is differentiation- and cell cycle-regulated in the ML-1 cells. We raised polyclonal antibodies against a glutathione S-transferase-cyclin A1 fusion protein produced in Escherichia coli. In immunoblot analyses, the antibodies recognized the Mr 65,000 cyclin A1 protein in ML-1 cells. The anti-cyclin A1 also immunoprecipitated the Mr 65,000 cyclin A1, along with the Mr 33,000 cyclin-dependent kinase (CDK) 2 and other proteins at Mr 39,000, 42,000, 45,000, 95,000, and 110,000. In an in vitro kinase assay, the CDK2-cyclin A1 complex precipitated by anti-cyclin A1 showed kinase activities against histone H1. In a yeast two-hybrid assay, cyclin A1 can bind to CDK2 but not to CDC2, CDK4, and CDK5. We mapped the human cyclin A1 gene to chromosome 13q12.3-q13, approximately 1000 kb from the sequence-tagged site marker WI-3374.

Pubmed ID: 9041194


  • Yang R
  • Morosetti R
  • Koeffler HP


Cancer research

Publication Data

March 1, 1997

Associated Grants

  • Agency: NCI NIH HHS, Id: CA26038
  • Agency: NCI NIH HHS, Id: CA42710
  • Agency: NCI NIH HHS, Id: CA70675-01

Mesh Terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • CDC2-CDC28 Kinases
  • Cell Cycle
  • Cell Differentiation
  • Chromosomes, Human, Pair 13
  • Cloning, Molecular
  • Cyclin A
  • Cyclin A1
  • Cyclin-Dependent Kinase 2
  • Cyclin-Dependent Kinases
  • Cyclins
  • Gene Expression Regulation, Neoplastic
  • Genes
  • Hematopoiesis
  • Humans
  • Leukemia, Myeloid
  • Male
  • Mice
  • Molecular Sequence Data
  • Protein Binding
  • Protein Kinases
  • Protein-Serine-Threonine Kinases
  • RNA, Messenger
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Testis
  • Xenopus Proteins
  • Xenopus laevis