Cloning, Expression, Purification and Crystallization of the PR Domain of Human Retinoblastoma Protein-Binding Zinc Finger Protein 1 (RIZ1)

Abstract

Through alternative promoter usage, human retinoblastoma protein-interacting zinc finger gene RIZ encodes two different protein products, RIZ1 and RIZ2, which have been identified to be a tumor suppressor and a proto-oncoprotein, respectively. Structurally, the two protein products share the same amino acid sequences except that RIZ2 lacks an N-terminal PR domain with methyltransferase activity. Previous studies have shown that over-expression of RIZ2 is usually associated with depressed RIZ1 expression in different human cancers. It is generally believed that RIZ1 and RIZ2 regulate normal cell division and function using a "Yin-Yang" fashion and the PR domain is responsible for the tumor suppressing activity of RIZ1. In order to better understand the biological functions of the PR domain by determining its three-dimensional crystal structure, we expressed, purified and crystallized a construct of the PR domain (amino acid residues 13-190) in this study. The maximum size of the needle-shaped crystals was approximately 0.20 x 0.01 x 0.01 mm.

Lower PRDM2 expression is associated with dopamine-agonist resistance and tumor recurrence in prolactinomas

“…As a new tumor suppressor, PRDM2 has been analyzed in a few reports, which have attempted to explain the reasons the gene is inactivated in cancer cells. Genetic and epigenetic changes are thought to be responsible [ 29 , 30 ]. According to a genetic perspective, PRDM2 may be down-regulated by chromosomal instability and microsatellite instability, as well as frame-shift mutations, point mutations and heterozygote deficiency [ 14 , 29 , 31 ].…”

“…Genetic and epigenetic changes are thought to be responsible [ 29 , 30 ]. According to a genetic perspective, PRDM2 may be down-regulated by chromosomal instability and microsatellite instability, as well as frame-shift mutations, point mutations and heterozygote deficiency [ 14 , 29 , 31 ]. From an epigenetic perspective, the deactivation of PRDM2 may occur due to promoter methylation and histone acetylation [ 32 ].…”

Tumor Suppressor RIZ1 in Carcinogenesis

“…The ability of RIZ1 to methylate H3K9 was depleted by the Ile188V mutation and decreased by the Cys106Tyr and Ala159Val mutations [49]. Transfection with cDNA encoding only the PR domain and its C-terminal neighboring region (amino acid residues 13-190) of RIZ1 significantly increased the cell death of hepatoma HuH7 cells, implicating that the PR domain possesses tumor suppressing activity even without the help of the other functional domains [47,50]. The Rb-binding domain interacts with the C-terminus of retinoblastoma protein (Rb), which is an important tumor suppressor [51].Since Rb is a common target for viral oncoproteins, it has been speculated that oncoviral proteins may structurally mimic RIZ proteins (RIZ1 and RIZ2) to interact with Rb and alter its biological function [51].…”

Effects of triptolide on RIZ1 expression, proliferation, and apoptosis in multiple myeloma U266 cells

“…The retinoblastoma protein-interacting zinc-finger (RIZ) gene, located on 1p36, is a recently described tumor suppressor gene and a member of the protein methyltransferase superfamEffects of triptolide on RIZ1 expression, proliferation, and apoptosis in multiple myeloma U266 cells Fei [11] . The RIZ gene encodes two proteins, RIZ1 and RIZ2.…”

“…In AML cell lines and patient samples, RIZ1 expression is reduced relative to normal bone marrow. In addition, the RIZ1 knockout mouse has a high incidence of diffuse large B-cell lymphoma [11] . In chronic myelogenous leukemia (CML), blastic transformation is associated with the loss of heterozygosity in the chromosomal region containing RIZ1 [16] .…”