17 research outputs found
Coexistence of different base periodicities in prokaryotic genomes as related to DNA curvature, supercoiling, and transcription
We analyzed the periodic patterns in E. coli promoters and compared the
distributions of the corresponding patterns in promoters and in the complete
genome to elucidate their function. Except the three-base periodicity,
coincident with that in the coding regions and growing stronger in the region
downstream from the transcriptions start (TS), all other salient periodicities
are peaked upstream of TS. We found that helical periodicities with the lengths
about B-helix pitch ~10.2-10.5 bp and A-helix pitch ~10.8-11.1 bp coexist in
the genomic sequences. We mapped the distributions of stretches with A-, B-,
and Z- like DNA periodicities onto E.coli genome. All three periodicities tend
to concentrate within non-coding regions when their intensity becomes stronger
and prevail in the promoter sequences. The comparison with available
experimental data indicates that promoters with the most pronounced
periodicities may be related to the supercoiling-sensitive genes.Comment: 23 pages, 6 figures, 2 table
Nucleosomes in gene regulation: theoretical approaches
This work reviews current theoretical approaches of biophysics and
bioinformatics for the description of nucleosome arrangements in chromatin and
transcription factor binding to nucleosomal organized DNA. The role of
nucleosomes in gene regulation is discussed from molecular-mechanistic and
biological point of view. In addition to classical problems of this field,
actual questions of epigenetic regulation are discussed. The authors selected
for discussion what seem to be the most interesting concepts and hypotheses.
Mathematical approaches are described in a simplified language to attract
attention to the most important directions of this field
Thirty years of geological investigations with the use of space facilities: Trends, achievements, and prospects
Active faults in the Eastern hemisphere.
The Project ââWorld Map of Major Active Faultsââ
was initiated in 1989 and was approved by the International
Lithosphere Commission in 1990 under the
chairmanship of Vladimir G. Trifonov (Russia) as
Project II-2 of the International Lithosphere Program
(ILP). The Project was supported by UNESCO as a
contribution of the ILP to the UN International Decade
of Natural Disaster Reduction. In 1991, the Project was
separated for better management into two sub-projects
including correspondingly representatives from the
Eastern and Western Hemispheres. Dr. M.S. Machette
(USGS, Denver, USA) was approved as a co-chairman
for the Western Hemisphere sub-project.
Because knowledge of location, parameters and
contemporary behavior of active faults is important
and even necessary not only for studying recent geodynamics
and rock deformation, but also for estimating
various natural hazards and especially seismic
ones, the ILP Project II-2 was included in 1993 in
the ILP Global Seismic Hazard Assessment Program