Alternatively spliced cyclin C mRNA is widely expressed, cell cycle regulated, and encodes a truncated cyclin box

Oncogene. 1996 Aug 15;13(4):705-12.

Abstract

The cyclin C protein has recently been shown to associate with a unique cyclin dependent protein kinase (cdk8) and it has been proposed that this complex may regulate RNA transcription during the cell cycle. In addition, the human cyclin C gene has been localized to human chromosome 6q21 and it was found to be frequently deleted in a subset of acute lymphoblastic leukemias (ALL's). Screening of an avian T-cell cDNA library resulted in the isolation of a cyclin C homologue as well as an abundant, yet distinct, cyclin C-related cDNA. The predicted open reading frame (ORF) of the cyclin C cDNA predicted a 283 amino acid protein that was > 99% identical to the human protein and 72% identical to the Drosophila melanogaster protein. However, the predicted ORF of the cyclin C-related cDNA predicted a much smaller 105 amino acid protein that was identical to cyclin C well into the cyclin-box region (amino acid residue 98), where it abruptly diverges and then terminates. Using PCR analysis of cDNA derived from a range of cell lines and tissues, alternative splicing of the avian cyclin C gene has been demonstrated. Furthermore, a smaller approximately 19 kDa protein that co-migrates with the in vitro transcribed and translated truncated cyclin C protein was detected in normal and virally-transformed avian cells with a cyclin C-specific antibody. Expression of alternatively spliced cyclin C mRNA and protein is regulated in a cell cycle-dependent manner reminiscent of cyclin B2. The function of this truncated cyclin C protein is not known, but its expression in avian cells suggest that this truncated cyclin C protein may participate as an early endogenously encoded cyclin C inhibitor.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alternative Splicing*
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cell Cycle / genetics*
  • Cell Line
  • Chickens
  • Cloning, Molecular
  • Cyclin C
  • Cyclins / genetics*
  • DNA, Complementary
  • Humans
  • Molecular Sequence Data
  • Open Reading Frames
  • RNA, Messenger / genetics*
  • Sequence Homology, Amino Acid

Substances

  • CCNC protein, human
  • CycC protein, Drosophila
  • Cyclin C
  • Cyclins
  • DNA, Complementary
  • RNA, Messenger

Associated data

  • GENBANK/U40873
  • GENBANK/U40874
  • GENBANK/U40875
  • GENBANK/U40876
  • GENBANK/U40877
  • GENBANK/U40878
  • GENBANK/U40879
  • GENBANK/U40880
  • GENBANK/U40881
  • GENBANK/U40882
  • GENBANK/U40883
  • GENBANK/U40884
  • GENBANK/U40885
  • GENBANK/U40886