J Appl Biomed 5:49-56, 2007 | DOI: 10.32725/jab.2007.007

Nucleolar proteins change in altered gravity

Margarita A. Sobol^1,2,*, Fernando González-Camacho², Elizabeth L. Kordyum¹, Francisco Javier Medina²

¹ Institute of Botany (NASU), 01004 Kiev, Ukraine

² Centro de Investigaciones Biológicas (CSIC), E-28040 Madrid, Spain

Nucleolin is a major highly phosphorylated nucleolar protein involved in the regulation of r-chromatin condensation/expansion and rDNA transcription as well as in rRNA processing. The nucleolar protein homologous to the mammalian nucleolin and to the onion nucleolin-like protein NopA100, was detected in the nuclear soluble protein fraction, and in the nuclear matrix fraction from Lepidium sativum root meristematic cells, using the selective silver staining method and the cross-reaction with the anti-NopA100 antibody. In 2-DE Western blots of both nuclear fractions, the nucleolin-like protein was revealed as a smear on the level of 90 kDa extending through a certain range of pI. In both extracts obtained from seedlings germinated and grown under slow clinorotation, the extension of the pI range was shorter and the molecular weight range was thinner than in the 1 g control; moreover, in the nuclear matrix fraction, the spread of the pI range was separated into two clusters. The results obtained could indicate a lower phosphorylation of the protein, suggesting a decrease in the activity of L. sativum nucleolin-like protein under clinorotation.

Keywords: clinorotation; Lepidium sativum; nucleolus; nucleolin-like protein; two-dimensional immunoblotting

Received: January 16, 2007; Revised: January 23, 2007; Published: March 31, 2007  Show citation