Rat intestinal crypt-cell replication factor with homology to early S-phase proteins required for cell division.
Cell proliferation requires inhibitory and permissive factors to monitor cell-cycle progression and control DNA replication. The small intestine has a high rate of proliferation and a very low incidence of cancer, suggestive of efficient mechanisms for control of the cell cycle and assuring fidelity of DNA replication. We have isolated a cDNA from a rat crypt-cell library which hybridized to a 3.0-kb mRNA specific for crypt cells, the proliferative cell compartment of the intestine. Its amino-acid sequence indicates that it is a new member of a family of replication proteins found in yeast, Cenorhabditis elegans, mouse and humans. Its transcripts were markedly increased in fetal rat intestine and liver, decreased in long-term confluent and serum-starved tissue culture cells (IEC cells, a cell line derived from rat crypt cells), increased with serum repletion as cells resumed proliferation, and appeared to be species specific. Isolation and functional characterization of small intestinal crypt-cell replication factors should help explain this organ's low incidence of cancer.
Sykes
D E
DE
Department of Medicine, State University of New York at Buffalo 14203, USA.
Weiser
M M
MM
D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D002455:Cell Division; D002460:Cell Line; D003001:Cloning, Molecular; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism*; D008969:Molecular Sequence Data; D051381:Rats; D016196:S Phase; D016415:Sequence Alignment
D018797:Cell Cycle Proteins