Inhibition of nucleolar protein nucleolin by electroporation with anti-nucleolin antibodies results in an increase of the nucleolar size

• Published in: Biology of the cell 1998-07, Vol.90 (4), p.355-361
• Main Authors: Abadía-Molina, Francisco, Torreblanca, José, García-Herdugo, Gregorio, Moreno, Francisco J
• Format: Article
• Language: English
• Subjects: Antibodies - administration & dosage; C23; Cell Line; Cell Nucleolus - metabolism; Cell Nucleolus - ultrastructure; Electroporation; Humans; image analysis; Microscopy, Electron; Nuclear Proteins - antagonists & inhibitors; Nuclear Proteins - immunology; Nuclear Proteins - metabolism; Nucleolin; nucleolus; Phosphoproteins - antagonists & inhibitors; Phosphoproteins - immunology; Phosphoproteins - metabolism; RNA Precursors - metabolism; RNA Processing, Post-Transcriptional; RNA-Binding Proteins - antagonists & inhibitors; RNA-Binding Proteins - immunology; RNA-Binding Proteins - metabolism
• ISSN: 0248-4900; 1768-322X
• DOI: 10.1016/S0248-4900(98)80016-6

Electroporation of exponentially growing human larynx epidermoid carcinoma cells (HEp-2) with a serum against nucleolin, one of the most abundant non-histone nuclear proteins, has shown, 24 h after electroporation, a significant increase in the size of the nucleolus of these cells compared with normal HEp-2 cells (non-electroporated) and electroporated HEp-2 cells in the absence of antinucleolin serum ( P < 0.01). Image analysis evaluation of the different nucleolar components proved a major contribution of the dense fibrillar component to the total nucleolar size in cells electroporated with anti-nucleolin antibodies, more than that corresponding to the dense fibrillar component in cells from any of the control groups ( P < 0.01), indicating that the reported increase in nucleolar size was due to a marked enlargement of the dense fibrillar regions. These results, in agreement with previous biochemical and molecular biology studies, suggest a pivotal role for nucleolin in pre-rRNA processing and constitute morphological evidence supporting this role. Following nucleolin inhibition, impaired pre-rRNA processing might result in an accumulation of this molecular species in the dense fibrillar component of the nucleolus, where pre-rRNA is first present.