Identification of CASZ1 NES reveals potential mechanisms for loss of CASZ1 tumor suppressor activity in neuroblastoma.
As a transcription factor, localization to the nucleus and the recruitment of cofactors to regulate gene transcription is essential. Nuclear localization and nucleosome remodeling and histone deacetylase (NuRD) complex binding are required for the zinc-finger transcription factor CASZ1 to function as a neuroblastoma (NB) tumor suppressor. However, the critical amino acids (AAs) that are required for CASZ1 interaction with NuRD complex and the regulation of CASZ1 subcellular localization have not been characterized. Through alanine scanning, immunofluorescence cell staining and co-immunoprecipitation, we define a critical region at the CASZ1 N terminus (AAs 23-40) that mediates the CASZ1b nuclear localization and NuRD interaction. Furthermore, we identified a nuclear export signal (NES) at the N terminus (AAs 176-192) that contributes to CASZ1 nuclear-cytoplasmic shuttling in a chromosomal maintenance 1-dependent manner. An analysis of CASZ1 protein expression in a primary NB tissue microarray shows that high nuclear CASZ1 staining is detected in tumor samples from NB patients with good prognosis. In contrast, cytoplasmic-restricted CASZ1 staining or low nuclear CASZ1 staining is found in tumor samples from patients with poor prognosis. These findings provide insight into mechanisms by which CASZ1 regulates transcription, and suggests that regulation of CASZ1 subcellular localization may impact its function in normal development and pathologic conditions such as NB tumorigenesis.
Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD, USA.
Z
Z
Liu
Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD, USA.
N
N
Lam
Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD, USA.
E
E
Wang
Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD, USA.
R A
RA
Virden
Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA.
B
B
Pawel
Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA.
E F
EF
Attiyeh
Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA.
J M
JM
Maris
Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD, USA.
C J
CJ
Thiele
D000595:Amino Acid Sequence; D001665:Binding Sites; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D009154:Mutation; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism*; D049790:Nuclear Export Signals; D011485:Protein Binding; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D059467:Transcriptome; D025521:Tumor Suppressor Proteins / Q000737:chemistry / Q000378:metabolism*
C511127:CASZ1 protein, human; D004268:DNA-Binding Proteins; D049790:Nuclear Export Signals; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins