SummarySelected barley miRNAs and their targets are regulated upon heat stress. Splicing of introns carrying miRNAs was induced by heat and correlated with the accumulation of mature miRNA.

The bacterial protein Hfq participates in the regulation of translation by small noncoding RNAs (sRNAs). Several mechanisms have been proposed to explain the role of Hfq in the regulation by sRNAs binding to the 5 ′ -untranslated mRNA regions. However, it remains unknown how Hfq affects those sRNAs that target the coding sequence. Here, the contribution of Hfq to the annealing of three sRNAs, RybB, SdsR, and MicC, to the coding sequence of Salmonella ompD mRNA was investigated. Hfq bound to ompD mRNA with tight, subnanomolar affinity. Moreover, Hfq strongly accelerated the rates of annealing of RybB and MicC sRNAs to this mRNA, and it also had a small effect on the annealing of SdsR. The experiments using truncated RNAs revealed that the contributions of Hfq to the annealing of each sRNA were individually adjusted depending on the structures of interacting RNAs. In agreement with that, the mRNA structure probing revealed different structural contexts of each sRNA binding site. Additionally, the annealing of RybB and MicC sRNAs induced specific conformational changes in ompD mRNA consistent with local unfolding of mRNA secondary structure. Finally, the mutation analysis showed that the long AU-rich sequence in the 5 ′ -untranslated mRNA region served as an Hfq binding site essential for the annealing of sRNAs to the coding sequence. Overall, the data showed that the functional specificity of Hfq in the annealing of each sRNA to the ompD mRNA coding sequence was determined by the sequence and structure of the interacting RNAs.

MgrR is an Hfq-dependent sRNA, whose transcription is controlled by the level of Mg ions in MgrR belongs to Class II sRNAs because its stability in the cell is affected by mutations in Hfq differently than canonical, Class I sRNAs. Here, we examined the effect of mutations in RNA binding sites of Hfq on the kinetics of the annealing of MgrR to two different target mRNAs, and , by global data fitting of the reaction kinetics monitored by gel electrophoresis of intermediates and products. The data showed that the mutation on the rim of the Hfq ring trapped MgrR on Hfq preventing the annealing of MgrR to either mRNA. The mutation in the distal face slowed the ternary complex formation and affected the release of MgrR-mRNA complexes from Hfq, while the mutation in the proximal face weakened the MgrR binding to Hfq and in this way affected the annealing. Moreover, competition assays established that MgrR bound to both faces of Hfq and competed against other sRNAs. Further studies showed that uridine-rich sequences located in less structurally stable regions served as Hfq binding sites in each mRNA. Overall, the data show that the binding of MgrR sRNA to both faces of the Hfq ring enables it to efficiently anneal to target mRNAs. It also confers on MgrR a competitive advantage over other sRNAs, which could contribute to efficient cellular response to changes in magnesium homeostasis.

Wstęp. Szczepienia są najbezpieczniejszą i sprawdzoną wiele lat temu drogą nabycia odporności. W Unii Europejskiej w profilaktyce COVID-19 zarejestrowane zostały dwie szczepionki mRNA oraz dwie szczepionki wektorowe oparte na zmodyfikowanych adenowirusach. Niepożądane odczyny poszczepienne (NOP) są to wszelkie nieprawidłowe reakcje organizmu lub zdarzenia następujące po szczepieniu. Reakcje te mogą mieć różne nasilenie -od łagodnych po rzadko występujące odczyny poważne, czy nawet zagrażające życiu. Cel pracy. Celem pracy była ocena niepożądanych odczynów poszczepiennych u pacjentów szczepionych przeciwko SARS--CoV-2. Materiał i metody. Badaniem objęto 376 osób, przeprowadzono je metodą sondażu diagnostycznego. Kryterium włączenia do badania było przebycie szczepienia przeciwko wirusowi SARS-CoV-2. W związku z brakiem standaryzowanych narzędzi dostosowanych do zaplanowanych badań posłużono się ankietą własnego autorstwa skonstruowaną z 15 pytań. Wyniki. Spośród badanych 37,3% otrzymało dwie dawki szczepionki. U 47,9% nie wystąpiły żadne reakcje poszczepienne. Odnotowano istotny związek pomiędzy wiekiem ankietowanych [χ 2 (2; N = 376) = 5,74; p < 0,05; V = 0,24], chorobami nerek (p = 0,019), występowaniem nadciśnienia tętniczego (p = 0,0003), chorobami nowotworowymi (p = 0,047), przewlekłymi chorobami układu oddechowego (p = 0,015), liczbą przyjmowanych leków [χ 2 (2; N = 376) = 5,62; p < 0,05; V = 0,23] oraz kolejnymi dawkami szczepienia dwudawkowego [χ 2 (2; N = 376) = 4,23; p < 0,05; V = 0,34]. Wnioski. Stosowane szczepionki anty-COVID-19, niezależnie od działania mechanizmu, okazały się bezpieczne. NOP częściej występują u ludzi w podeszłym wieku cierpiących z powodu współistniejących chorób i przyjmujących na stałe 3-5 leków. Częściej ujawniają się po podaniu drugiej dawki szczepionki.

The bacterial Sm-like protein Hfq affects the regulation of translation by small noncoding RNAs (sRNAs). In this way, Hfq participates in the cell adaptation to environmental stress, regulation of cellular metabolism, and bacterial virulence. The majority of known sRNAs bind complementary sequences in the 5'-untranslated mRNA regions. However, recent studies have shown that sRNAs can also target the mRNA coding sequence, even far downstream of the AUG start codon. In this review, we discuss how Hfq contributes to the translation regulation by those sRNAs which bind to the mRNA coding sequence.

Small bacterial RNAs (sRNAs) regulate translation by pairing with complementary sequences in their target mRNAs, in a process which is often dependent on the Hfq protein. Here, the secondary structure of a 95-nt long fragment of Salmonella fadL mRNA containing RybB sRNA binding site in the coding region was analyzed. The data indicated local rearrangements in this mRNA structure after the annealing of RybB. The filter retention data had shown that Hfq bound both RybB and the fadL mRNA fragment with tight affinities. Moreover, Hfq increased the rate of RybB annealing to fadL mRNA. These data indicate that Hfq directly participates in RybB interactions with the fadL mRNA.

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