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Естественные науки
Маланин С.Ю., Барабанщиков Б.И. Рибосвичи - новый класс регуляторов генной активности // Учен. зап. Казан. ун-та. Сер. Естеств. науки. - 2011. - Т. 153, кн. 2. - С. 73-88.
УДК 575:57.012.6
РИБОСВИЧИ - НОВЫЙ КЛАСС РЕГУЛЯТОРОВ ГЕННОЙ АКТИВНОСТИ
С.Ю. Маланин, Б.И. Барабанщиков Аннотация
В обзоре представлены данные о регуляции генной активности с помощью рибос-вичей (riboswitch). Рибосвичи представляют собой некодирующие элементы мРНК, которые способны связывать низкомолекулярные лиганды и тем самым регулировать транскрипцию, трансляцию, стабильность и альтернативный сплайсинг РНК транс-криптов. Контроль экспрессии в данном случае происходит без участия факторов белковой природы. Рибосвичи состоят из двух доменов: высоко-консервативного аптамера, ответственного за связывание лиганда, и экспрессионной платформы, которая регулирует экспрессию гена, изменяя вторичную структуру РНК. У грамотрицательных бактерий изменение вторичной структуры РНК в большинстве случаев приводит к экранированию последовательности Шайн - Дальгарно и блокированию инициации трансляции, тогда как у грамположительных бактерий - к аттенуации транскрипции. Рибосвичи являются широко распространенным механизмом регуляции генной активности. Данные риборегуляторы обнаружены не только в бактериях и археях, но и в эукариотических организмах (некоторых видах грибов и растений). Рибосвичи принимают участие в регуляции метаболизма витаминов, аминокислот, пуринов и некоторых других молекул.
Ключевые слова: рибосвич, лиганды, регуляция экспрессии гена, бактерии, ара-бидопсис.
Summary
S.Yu. Malanin, B.I. Barabanschikov. Riboswitches Are a New Class of Gene Expression Regulators.
Regulation of gene expression by riboswitches is discussed in the present review. Riboswitches are noncoding RNA elements which directly bind small molecule ligands and regulate transcription, translation, stability and alternative splicing of RNA transcripts. The control of gene expression in this case occurs without protein factors, therefore riboswitches may be considered as ancient regulatory systems, which evolved during the prebiotic RNA world. A riboswitch is composed of two domains: a 5' highly conserved aptamer domain responsible for specific binding of a small molecule and a downstream expression platform that regulates expression by alteration of RNA secondary structure. In Gram-negative bacteria, such switch in the secondary structure leads to the sequestration of SD (Shine-Dalgarno) sequence, whereas in Gram-positive bacteria an attenuation of transcription occurs in most cases. Riboswitches are a widespread mechanism for regulation of gene expression. These elements were found not only in bacteria and archaea, but also in eukaryotic organisms (several species of fungi and plants).
Moreover, riboswitches affect many metabolic pathways in cells; synthesis of vitamins, amino acids, purins and several other molecules is regulated by the given mechanism.
The current review describes the discovery and methods for investigation of these ri-boregulators. A description of all known riboswitch classes is also given based on classification of its cognate ligands. The review contains our own data about the regulation of thiamine synthesis in Arabidopsis plants by TPP riboswitch by means of alternative splicing control. Moreover, practical applications of natural and artificial riboswitches are considered which can be used as antibacterial drug targets or tools for regulation of gene expression in functional genomics and biotechnology.
Key words: riboswitch, ligands, regulation of gene expression, bacteria, Arabidopsis.
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Поступила в редакцию 16.12.10
Маланин Сергей Юрьевич - инженер кафедры генетики Казанского (Приволжского) федерального университета. E-mail: sergen83@mail.ru
Барабанщиков Борис Иванович - доктор биологических наук, профессор кафедры генетики Казанского (Приволжского) федерального университета. E-mail: Boris.Barabanchikov@ksu.ru
