Plant cells contain a novel member of the retinoblastoma family of growth regulatory proteins

Xie, Q., Sanz-Burgos, A. P., Hannon, G. J., Gutiérrez, C. (1996) Plant cells contain a novel member of the retinoblastoma family of growth regulatory proteins. EMBO Journal, 15 (18). pp. 4900-4908. ISSN 02614189 (ISSN)



The product of the retinoblastoma susceptibility gene (Rb) controls the passage of mammalian cells through G1 phase. Animal virus oncoproteins interact with the Rb protein via an LXCXE motif anti disrupt Rb-E2F complexes, driving cells into S-phase. Recently, we found that the RepA protein of a plant geminivirus contains an LXCXE motif that is essential for its function, a finding that predicts the existence of Rb-related proteins in plant cells. Here we report the isolation of a maize cDNA clone encoding a protein (ZmRb1) which, based on structural and functional studies, is closely related to the mammalian Rb family of growth regulatory proteins. ZmRb1 shows a high degree of amino acid conservation when compared with animal Rb members, particularly in the A/B 'pocket' domain, but ZmRb1 has a shorter N-terminal domain, ZmRb1 forms stable complexes with plant LXCXE-containing proteins, e.g. geminivirus RepA protein. Geminivirus DNA replication is reduced in plant cells transfected with plasmids encoding either ZmRb1 or human p130, a member of the Rb family. This suggests that ZmRb1 controls the G1/S transit in plant cells and is consistent with the fact that geminiviruses need an S-phase environment for DNA replication, as animal DNA tumor viruses do. Our results allow the extension of the Rb family of tumor suppressor proteins to plants and have implications on animal and plant strategies for cell growth control.

Item Type: Paper
Uncontrolled Keywords: Cell cycle DNA replication Geminivirus Retinoblastoma Two-hybrids retinoblastoma protein amino acid sequence article growth regulation nonhuman plant cell priority journal tumor suppressor gene Base Sequence Blotting, Northern Cell Cycle Proteins DNA, Complementary DNA, Viral Geminiviridae Genes, Retinoblastoma Humans Molecular Sequence Data Open Reading Frames Plant Growth Regulators Plant Proteins Sequence Alignment
Subjects: organism description > plant
diseases & disorders > cancer > cancer types > retinoblastoma
CSHL Authors:
Communities: CSHL labs > Hannon lab
Depositing User: Matt Covey
Date: 1996
Date Deposited: 09 Jan 2013 17:00
Last Modified: 09 Jan 2013 17:00
PMCID: PMC452227
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