dTrmt10A impacts Hsp70 chaperone mA levels and the stress response in the Drosophila brain.

Chronic cellular stress has a profound impact on the brain, leading to degeneration and accelerated aging. Recent work has revealed the vital role of RNA modifications, and the proteins responsible for regulating them, in the stress response. In our study, we defined the role of CG14618/dTrmt10A, the Drosophila counterpart of human TRMT10A a N-methylguanosine methyltransferase, on mA regulation and heat stress resilience in the Drosophila brain.

Mettl3-catalyzed mA regulates histone modifier and modification expression in self-renewing somatic tissue.

-methyladenosine (mA) is the most abundant modification on messenger RNAs (mRNAs) and is catalyzed by methyltransferase-like protein 3 (Mettl3). To understand the role of mA in a self-renewing somatic tissue, we deleted in epidermal progenitors in vivo. Mice lacking demonstrate marked features of dysfunctional development and self-renewal, including a loss of hair follicle morphogenesis and impaired cell adhesion and polarity associated with oral ulcerations.

Noncatalytic regulation of 18 rRNA methyltransferase DIMT1 in acute myeloid leukemia.

Several rRNA-modifying enzymes install rRNA modifications while participating in ribosome assembly. Here, we show that 18 rRNA methyltransferase DIMT1 is essential for acute myeloid leukemia (AML) proliferation through a noncatalytic function. We reveal that targeting a positively charged cleft of DIMT1, remote from the catalytic site, weakens the binding of DIMT1 to rRNA and mislocalizes DIMT1 to the nucleoplasm, in contrast to the primarily nucleolar localization of wild-type DIMT1.

Cyclic and Lasso Peptides: Sequence Determination, Topology Analysis, and Rotaxane Formation.

A broadly applicable chemical cleavage methodology to facilitate MS/MS sequencing was developed for macrocyclic and lasso peptides, which hold promise as exciting new therapeutics. Existing methods such as Edman degradation, CNBr cleavage, and enzymatic digestion are either limited in scope or completely fail in cleavage of constrained nonribosomal peptides. Importantly, the new method was utilized for synthesizing a unique peptide-based rotaxane (both cyclic and threaded) from the lasso peptide, benenodin-1 ΔC5.

Oxazolidinone-Mediated Sequence Determination of One-Bead One-Compound Cyclic Peptide Libraries.

A novel one-bead one-compound (OBOC) dual ring-opening/cleavage approach for cyclic peptide sequencing was developed. The method selectively modifies serine, cysteine, threonine, and/or glutamic acid to an oxazolidinone-derived moiety, thereby increasing the susceptibility of the modified peptide backbone toward hydrolysis. The resulting linear peptide was then sequenced in 1 min by tandem mass spectrometry on a quadrupole time-of-flight instrument incorporating two-dimensional liquid chromatography and ion mobility spectrometry separation.