Subnucleolar location of fibrillarin and NopA64 in Lepidium sativum root meristematic cells is changed in altered gravity.

Fibrillarin and the plant nucleolin homolog NopA64 are two important nucleolar proteins involved in pre-rRNA processing. In order to determine the effects of the altered gravity environment on the nucleolus, we have investigated the location of fibrillarin and NopA64 in nucleolar subcomponents of cress (Lepidium sativum L.) root meristematic cells grown under clinorotation, which reproduces an important feature of microgravity, namely, the absence of the orienting action of a gravity vector, and compared it to the location in control cells grown in normal 1 g conditions.

Alterations of the intranucleolar DNA localization caused by simulated microgravity.

The functions of the nucleolus responsible for the biosynthesis of ribosomes in altered gravity are still unclear. The location of nucleolar DNA both in control and simulated microgravity with fluorescent and immunogold cytochemistry was investigated. We determined firstly the redistribution of rDNA in the nucleolar components accompanied with the changes in their ultrastructure.

[Altered gravity affects subnucleolus localization of fibrillarin and NopA64, the most important proteins of rRNA processing].

Fibrillarin and plant nucleolin homologue NopA64 are two important nucleolar proteins involved in pre-rRNA processing. To understand better the effects of the altered gravity environment on the nucleolus functioning we have investigated the location of fibrillarin and NopA64 in nucleolar subcomponents of cress (Lepidium sativum L.) root meristematic cells grown under simulated microgravity that was compared to the control cells grown in normal conditions at I g.