We report the primary characterization of a new gene KCNRG mapped at chromosome band 13q14.3. This gene includes three exons and has two alternatively spliced isoforms that are expressed in normal tissues and in some tumor cell lines. Protein KCNRG has high homology to tetramerization domain of voltage-gated K + channels. Using the patchclamp technique we determined that KCNRG suppresses K + channel activity in human prostate cell line LNCaP. It is known that selective blockers of K + channels suppress lymphocyte and LNCaP cell line proliferation. We suggest that KCNRG is a candidate for a B-cell chronic lymphocytic leukemia and prostate cancer tumor suppressor gene. ß

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Various abiotic stresses cause the appearance of reactive oxygen species (ROS) in plant cells, which seriously damage the cellular structures. The engineering of transgenic plants with higher production of ROS-scavenging enzyme in plant cells could protect the integrity of such a fine intracellular structure as the cytoskeleton and each cellular compartment. We analyzed the morphological changes in root tip cells caused by the application of iso-osmotic NaCl and Na2SO4 solutions to tomato plants harboring an introduced superoxide dismutase gene. To study the roots of tomato plants cultivar Belyi Naliv (WT) and FeSOD-transgenic line, we examined the distribution of ROS and enzyme-linked immunosorbent detection of α-tubulin. In addition, longitudinal sections of the root apexes were compared. Transmission electronic microscopy of atypical cytoskeleton structures was also performed. The differences in the microtubules cortical network between WT and transgenic plants without salt stress were detected. The differences were found in the cortical network of microtubules between WT and transgenic plants in the absence of salt stress. While an ordered microtubule network was revealed in the root cells of WT tomato, no such degree of ordering was detected in transgenic line cells. The signs of microtubule disorganization in root cells of WT plants were manifested under the NaCl treatment. On the contrary, the cytoskeleton structural organization in the transgenic line cells was more ordered. Similar changes, including the cortical microtubules disorganization, possibly associated with the formation of atypical tubulin polymers as a response to salt stress caused by Na2SO4 treatment, were also observed. Changes in cell size, due to both vacuolization and impaired cell expansion in columella zone and cap initials, were responsible for the root tip tissue modification.

The effects of fusicoccin (FC) on the early growth processes in sorghum ( Sorghum vulgare M.) seeds germinated in water and in 0.1 M or 0.2 M NaCl solutions were investigated. We studied the rate of seed imbibition, the onset of radicle protrusion, the occurrence of the first mitoses, the mitotic index, the distribution of cells according to the phases of the cell cycle, as well as the length and weight of roots. Seed imbibition was considerably accelerated by treating them with 5 × 10 -6 M FC for 1 h. In these FC-treated seeds placed on NaCl solutions, FC stimulated water influx into seeds, radicle protrusion, and occurrence of the first mitoses. FC pretreatment did not affect substantially the distribution of meristematic cells according to the periods of the cell cycle after 72 h of seed germination on water or 0.1 M NaCl. Root growth was inhibited by 0.1 M NaCl, but it was partially recovered in the presence of FC. 0.2 M NaCl caused a decrease in the mitotic index and in the number of cells in the S phase, an accumulation of cells in the G 2 period and in the prophase, as well as a considerable inhibition of root growth. FC pretreatment of seeds subsequently germinated on 0.2 M NaCl resulted in an increase in the number of cells in the G 1 period, in the mitotic index, and in the root-growth rate. FC virtually did not affect the growth of sorghum in the absence of salt. Pretreatment of seeds with FC followed by salinization resulted in an increase in the water content in seeds. It is suggested that a FC-induced increase in the water content of seeds accelerated metabolic processes in seeds germinating on NaCl solutions, thus regulating ionic homeostasis and thereby stimulating the initial growth processes.

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