Set1 is the catalytic subunit and the central component of the evolutionarily conserved Set1 complex (Set1C) that methylates histone 3 lysine 4 (H3K4). Here we have determined protein/protein interactions within the complex and related the substructure to function. The loss of individual Set1C subunits differentially affects Set1 stability, complex integrity, global H3K4 methylation, and distribution of H3K4 methylation along active genes. The complex requires Set1, Swd1, and Swd3 for integrity, and Set1 amount is greatly reduced in the absence of the Swd1-Swd3 heterodimer. Bre2 and Sdc1 also form a heteromeric subunit, which requires the SET domain for interaction with the complex, and Sdc1 strongly interacts with itself. Inactivation of either Bre2 or Sdc1 has very similar effects. Neither is required for complex integrity, and their removal results in an increase of H3K4 mono-and dimethylation and a severe decrease of trimethylation at the 5 end of active coding regions but a decrease of H3K4 dimethylation at the 3 end of coding regions. Cells lacking Spp1 have a reduced amount of Set1 and retain a fraction of trimethylated H3K4, whereas cells lacking Shg1 show slightly elevated levels of both di-and trimethylation. Set1C associates with both serine 5-and serine 2-phosphorylated forms of polymerase II, indicating that the association persists to the 3 end of transcribed genes. Taken together, our results suggest that Set1C subunits stimulate Set1 catalytic activity all along active genes.

Chirality-induced spin selectivity (CISS), the effect of helical molecules acting as room temperature hard magnets that confer spin polarization to electrical current, is an intriguing effect with potential applications in nanospintronics. In this scenario, molecules that are paramagnetic as well as helical would introduce a new degree of freedom in the same nano-scale device that has not been explored so far. Here, in order to investigate this idea, we propose the preparation of self-assembled monolayers (SAMs) based on a helical lanthanide binding tag peptide (LnLBTC) on a ferromagnetic substrate. We confirmed room temperature spin filtering of LnLBTC SAMs by well-established electrochemical approach and by direct local spin transport measurements in solid state devices. The latter were studied by a common liquid-metal drop electron transport system, easily implemented for spin dependent measurements. Electrochemistry shows an averaged spin polarization (SP) of ~5% in presence of a saturation magnetic field (H = 350 mT) while local measurements performed in solid state showed a SP of ~50 20% thanks to the reduction of the contribution of pure electron transport in non-covered areas. Calculations showed that conduction electrons interact strongly with the coordinated lanthanide ion, meaning a fixed chirality-based spin filtering can coexist with a spin filtering that is dependent on the polarization of the magnetic metal ion. This opens the door to all-organic single-molecule memristive devices.

A macroarray platform was used to identify binding sites of yeast histone acetyltransferase catalytic subunits and to correlate their positions with acetylation of lysine 14 of histone H3, revealing that Sas3p and Gcn5p are recruited to similar sets of intensely transcribed genes.

Molecular magnetism is reaching a degree of development that will allow for the rational design of sophisticated systems.