Federica Briani

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Sperm surface beta-N-acetylhexosaminidases are among the molecules mediating early gamete interactions in invertebrates and vertebrates, including man. The plasma membrane of Drosophila spermatozoa contains two beta-N-acetylhexosaminidases, DmHEXA and DmHEXB, which are required for egg fertilization. Here, we demonstrate that three putative Drosophila(More)
P4 is a natural phasmid (phage-plasmid) that exploits different modes of propagation in its host Escherichia coli. Extracellularly, P4 is a virion, with a tailed icosahedral head, which encapsidates the 11.6-kb-long double-stranded DNA genome. After infection of the E. coli host, P4 DNA can integrate into the bacterial chromosome and be maintained in a(More)
Upon cold shock Escherichia coli transiently stops growing and adapts to the new temperature (acclimatization phase). The major physiological effects of cold temperature are a decrease in membrane fluidity and the stabilization of secondary structures of RNA and DNA, which may affect the efficiencies of translation, transcription, and replication. Specific(More)
The genes required for replication of the temperate bacteriophage P4, which are coded by the phage left operon, are expressed from a constitutive promoter (PLE). In the lysogenic state, repression of the P4 replication genes is achieved by premature transcription termination. The leader region of the left operon encodes all the genetic determinants required(More)
Adaptation of Escherichia coli at low temperature implicates a drastic reprogramming of gene expression patterns. Mechanisms operating downstream of transcription initiation, such as control of transcription termination, mRNA stability and translatability, play a major role in controlling gene expression in the cold acclimation phase. It was previously(More)
Bacteriophage P4's superinfection immunity mechanism is unique among those of other known bacteriophages in several respects: (i) the P4 immunity factor is not a protein but a short, stable RNA (CI RNA); (ii) in the prophage the expression of the replication operon is prevented by premature transcription termination rather than by repression of(More)
S1 is an 'atypical' ribosomal protein weakly associated with the 30S subunit that has been implicated in translation, transcription and control of RNA stability. S1 is thought to participate in translation initiation complex formation by assisting 30S positioning in the translation initiation region, but little is known about its role in other RNA(More)
In the lysogenic state, bacteriophage P4 prevents the expression of its own replication genes, which are encoded in the left operon, through premature transcription termination. The phage factor responsible for efficient termination is a small, untranslated RNA (CI RNA), which acts as an antisense RNA and controls transcription termination by pairing with(More)
Bacillus subtilis pnpA gene product, polynucleotide phosphorylase (PNPase), is involved in double-strand break (DSB) repair via homologous recombination (HR) or non-homologous end-joining (NHEJ). RecN is among the first responders to localize at the DNA DSBs, with PNPase facilitating the formation of a discrete RecN focus per nucleoid. PNPase, which(More)
Polynucleotide phosphorylase (PNPase, polyribonucleotide nucleotidyltransferase, EC 2.7.7.8) is one of the cold shock-induced proteins in Escherichia coli and pnp, the gene encoding it, is essential for growth at low temperatures. We have analysed the expression of pnp upon cold shock and found a dramatic transient variation of pnp transcription profile:(More)