Anti-sense regions in satellite RNA of cucumber mosaic virus form stable complexes with the viral coat protein gene

Abstract

The interaction in vitro of the RNA of the Q-strain of cucumber mosaic virus (CMV) with its satellite RNA (sat-RNA) has been studied. In hybridisation reactions containing 30% formamide at 45 degrees, sat-RNA binds to CMV RNA 3 and 4 but not to CMV RNA 1 and 2 or RNA from tobacco mosaic virus and alfalfa mosaic virus. The viral coat protein gene present in RNA 3 and 4 contains the site of binding but this region does not contain complementary sequences of any significant length to the sat-RNA sequence. However, the optimum alignment of short complementary sequences present in these regions revealed a stable structure in which it is proposed that sat-RNA twists around the coat protein gene so that two separate blocks of nucleotides in sat-RNA base pair in opposite directions with two adjacent blocks in the coat protein gene to form a knot-like structure. The binding site is a region of 33 nucleotides within the coding region of the coat protein gene which base pairs with residues 98-113 and 134-152 of sat-RNA. The possibility of the binding region of sat-RNA functioning as an "anti-sense" sequence in regulation of the viral coat protein synthesis is discussed.

Satellite RNAs of plant viruses: structures and biological effects.

“…In vitro binding studies, however, detected stable complexes between satellite RNA and Q-CMV RNAs 3 and 4 (166). Therefore it has been suggested that CMV satellite RNA may regulate the expression of the coat protein gene from RNA 4 (166). However, using multiple strains of CMV and several CMV satellite RNAs, we were able to detect stable complexes involving CMV RNAs 2, 3, and 4 in various combinations, and none of these complexes inhibited the in vitro translation of coat protein from RNA 4 (40a).…”

Genetic Engineering in Crop Improvement

“…They do not exhibit any base sequence homology to the genomes of either virus or plant host, and they are replicated by the helper virus-coded RNA-dependent RNA polymerase. Evidence has been presented for a direct interaction of satellite and viral RNA (Rezaian and Symons, 1986), and for the attenuating activity of putative, satellite-encoded proteins (Owens and Kaper, 1977). In cases where the presence of satellite RNA attenuates the disease caused by the helper virus, satellite RNAs have been used as a biological control in crop protection, e.g.…”

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“…2. Схема построения плазмиды, продуцирующей антисмысловые транскрипты ТК-гена вируса герпеса [11]. Fig.…”

“…2. The construction diagram of recombinant plasmid coding for antisense RNA to HSV TK-gene [11]. единичной копии.…”

“…Аналогичным способом взаимодействия комплементарных РНК-противотранскриптов контролируется также копийность плазмиды рТ181 Staph, aureus [9], сходные черты имеет и механизм регуляции синтеза Q-белка -антитерминатора, необходимого для экспрессии поздних генов фага λ [10]. Обсуждается регуляторная роль сателлитной РНК вируса огуречной мозаики [11], которая, обладая участком комплементарности с геномной РНК этого вируса, может оказывать влияние на экспрессию гена белка оболочки. Показано [12], что по механизму взаимодействия комплементарных последовательностей регулируется и эффективность трансляции мРНК зеина, в молекуле которой на 5'-и З'-концах имеются инвертированные повторы.…”