Том 45, № 1 (2019)

The spliceosome is necessary for the removal of intron sequences in transcribed pre-mRNA in eukaryotic cells. More than 200 proteins are involved in the process of pre-mRNA splicing; they coordinate the alternative splicing of most eukaryotic genes, which participate in the regulation of a variety of important cellular processes. However, a growing number of studies demonstrate the functions of spliceosomal proteins that are not directly related to the splicing process, such as (1) R-loop formation, (2) DNA repair, (3) telomere elongation, (4) M phase regulation, and (5) mRNA export from the nucleus. In this review, we summarize the data on the noncanonical functions of the spliceosomal proteins. Taking into account the fact that mutations in spliceosomal genes are commonly found in tumor cells, a careful study of noncanonical functions of spliceosomal proteins may provide new insights into the development of effective methods of cancer treatment and design of drugs for delaying cell aging.

A scheme for analyzing the mass spectra of fragmented peptides, including chemical modification of the N-terminal amino group of the peptide by 5-(N,N-dimethylamino)naphthalene-1-sulfonyl chloride followed by ionization of the dansylated peptide by electrospray and its fragmentation at the low vacuum zone of the sample solution input unit into the mass spectrometer (ESI-o-TOF scheme), has been proposed. It is shown that the resulting ions are fragmented with the predominant formation of b-ions bearing a Dns-group. In this way, it is possible to obtain high-intensity b-ions (peak/noise intensity ratio of 10/1 to 100/1), including b₁ and b₂ ions that are especially valuable for determining the structure. In combination with the previously proposed method of obtaining informative y-ions, this approach allows one to reliably determine the complete amino acid sequence of peptides containing up to 10 amino acid residues, without using computer programs for analyzing the fragment composition of peptides.

The activity of divinyl ether synthase (EC: 4.2.1.121), an enzyme involved in the lipoxygenase cascade of unsaturated fatty acids in plants, has been found in the roots and stalks of asparagus Asparagus officinalis L. Incubation of homogenates of roots and/or etiolated stalks of Asparagus officinalis L. with linoleic acid results in the formation of mainly divinyl ether (9Z,11Z,1'E)-12-(1'-hexenyloxy)-9,11-dodecadienoic acid ((11Z)-etheroleic acid), as well as a minor amount of its geometric isomer (9Z,11E,1'E)-12-(1'-hexenyloxy)-9,11-dodecadienoic acid (etheroleic acid). These compounds are derived from linoleic acid by the sequential action of regiospecific 13-lipoxygenase and divinyl ether synthase. Moreover, a minor compound, whose amount increases after the incubation of homogenates with the 9-hydroperoxide of linoleic acid ((9S,10E,12Z)-9-hydroperoxy(10,12)–octadecadienoic acid), has been found. This compound has been identified as (8E,1'Z,3'Z)-9-(1',3'-nonadienyloxy)-8-nonenoic acid ((1'Z)-colneleic acid). These data suggest that nonphotosynthetic tissues of asparagus exhibit the activity of a novel 13/9-specific divinyl ether synthase.

6-(Benzo[d]thiazol-2-yl)-4-oxo-(4H)-chromene-3-carbaldehyde was utilized to construct a novel series of fused chromone bearing benzothiazole moiety, namely chromeno[2,3-b]azetol, benzo[c]chromene, and chromeno[2,3-c]pyrazole derivatives, as well as, non-fused chromones, such as thiazolidinone, pyrazolone, and pyridine derivatives. The in vitro antitumor activities of the synthesized products against six cancer cell lines, including A594, HCT-116, MCF-7, HepPG2, PC3, and HFB4, were evaluated. Some compounds exhibited significant anticancer activities against both lung and colon cancer cells very close to that of a standard drug doxorubicin.