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Maria Beatrice Boniotti

Publications and source records attributed to Maria Beatrice Boniotti.

4 recordsLinked to original sources
PubMed2006

Molecular and biological characterization of deformed wing virus of honeybees (Apis mellifera L.).

Deformed wing virus (DWV) of honeybees (Apis mellifera) is closely associated with characteristic wing deformities, abdominal bloating, paralysis, and rapid mortality of emerging adult bees. The virus was purified from diseased insects, and its genome was cloned and sequenced. The genomic RNA of DWV is 10,140 nucleotides in length and contains a single large open reading frame encoding a 328-kDa polyprotein. The coding sequence is flanked by a 1,144-nucleotide 5' nontranslated leader sequence and a 317-nucleotide 3' nontranslated region, followed by a poly(A) tail. The three major structural proteins, VP1 (44 kDa), VP2 (32 kDa), and VP3 (28 kDa), were identified, and their genes were mapped to the N-terminal section of the polyprotein. The C-terminal part of the polyprotein contains sequence motifs typical of well-characterized picornavirus nonstructural proteins: an RNA helicase, a chymotrypsin-like 3C protease, and an RNA-dependent RNA polymerase. The genome organization, capsid morphology, and sequence comparison data indicate that DWV is a member of the recently established genus Iflavirus.

Amino Acid Sequence↗
PubMed2002

PCNA protein associates to Cdk-A type protein kinases in germinating maize.

In higher eukaryotes, the proliferating cell nuclear antigen (PCNA) can be found associated to Cyclin D and Cdk4/6, the kinase complex responsible for cell cycle commitment in response to growth and mitogenic signals. During maize germination, PCNA can be found in protein complexes between 131 and 163 kDa. The sizes of PCNA protein complexes seem to change during germination, so that by the time the S phase starts, a complex of 100 kDa (likely the homotrimeric ring) is the predominant one. PCNA complexes during early germination contain (any of) two PSTAIRE-containing protein kinases of 32 and 36 kDa that readily phosphorylate both histone H1 and maize retinoblastoma-related (RBR) proteins. Kinase activity in PCNA complexes is markedly inhibited by roscovitine and olomoucine, two known Cdk inhibitors. The protein p13(Suc1) only pulls down the 36 kDa PSTAIRE protein. Kinase activity in PCNA immunoprecipitates is maximal during early germination, before the onset of the S-phase, whereas kinase activity associated to pl3(Suc1) reaches a peak later, after the onset of the S-phase. We discuss the physiological repercussions of these findings.

Algal Proteins↗
PubMed2002

Arabidopsis E2Fc functions in cell division and is degraded by the ubiquitin-SCF(AtSKP2) pathway in response to light.

Selective ubiquitin-mediated proteolysis through the cell cycle controls the availability, and therefore the activity, of several cell proliferation proteins. E2F transcription factors play distinct roles in both proliferating and differentiated cells by regulating gene expression. Here, we report that Arabidopsis AtE2Fc is regulated by a balance between gene expression and ubiquitin-proteasome proteolysis. AtE2Fc degradation implicates the function of the E3 ubiquitin-ligase Skp1, Cullin, F-box (SCF(AtSKP2)) complex and seems to be dependent on cyclin-dependent kinase phosphorylation. In addition, we found that AtE2Fc degradation is triggered by light stimulation of dark-grown seedlings. Interestingly, the auxin response mutant axr1-12, in which RUB1 modification of the SCF component CUL1 is impaired, shows increased AtE2Fc protein levels, suggesting a dysfunction in the control of AtE2Fc stability. Likewise, overexpression of a stable form of the AtE2Fc protein negatively affects cell division and increases cell size. These effects are mediated, at least in part, by downregulating the cell cycle gene AtCDC6. The negative role of AtE2Fc in gene expression is further supported by the fact that AtE2Fc interacts with plant retinoblastoma-related protein, suggesting that AtE2Fc might form part of a repressor complex. We propose that AtE2Fc might play a role in cell division and during the transition from skotomorphogenesis to photomorphogenesis.

Arabidopsis↗