Luisa Welp

• University of Göttingen

UV (ultra-violet) crosslinking with mass spectrometry (XL-MS) has been established for identifying RNA-and DNA-binding proteins along with their domains and amino acids involved. Here, we explore chemical XL-MS for RNA-protein, DNA-protein, and nucleotide-protein complexes in vitro and in vivo . We introduce a specialized nucleotide-protein-crossli...

Regulation of RNA helicase activity, often accomplished by protein cofactors, is essential to ensure target specificity within the complex cellular environment. The largest family of RNA helicase cofactors are the G-patch proteins, but the cognate RNA helicases and cellular functions of numerous human G-patch proteins remain elusive. Here, we disco...

The Mos kinase is a constitutive activator of the ERK/MAPK pathway exclusively expressed during oocyte meiosis, mediating key meiotic functions across animal species. While a few of its downstream effectors have been studied in some detail, molecular targets under the control of Mos-MAPK have not yet been identified systematically. Here, we combine...

Highlights: • Oocytes store essential proteins for early embryogenesis on cytoplasmic lattices • Cytoplasmic lattices are composed of periodic filaments with high surface area • Many stored proteins are required for epigenetic reprogramming of the embryo • Study links infertility phenotypes in women with stored protein function

The reaction of CO2 with H2O to form bicarbonate (HCO3⁻) and H⁺ controls sperm motility and fertilization via HCO3⁻-stimulated cAMP synthesis. A complex network of signaling proteins participates in this reaction. Here, we identify key players that regulate intracellular pH (pHi) and HCO3⁻ in human sperm by quantitative mass spectrometry (MS) and k...

The mechanisms by which viruses hijack the genetic machinery of the cells they infect are of current interest. When bacteriophage T4 infects Escherichia coli, it uses three different adenosine diphosphate (ADP)-ribosyltransferases (ARTs) to reprogram the transcriptional and translational apparatus of the host by ADP-ribosylation using nicotinamide...

5-Methyluridine (m5U) is one of the most abundant RNA modifications found in cytosolic tRNA. tRNA methyltransferase 2 homolog A (hTRMT2A) is the dedicated mammalian enzyme for m5U formation at tRNA position 54. However, its RNA binding specificity and functional role in the cell are not well understood. Here we dissected structural and sequence req...

The pentameric FERRY Rab5 effector complex is a molecular link between mRNA and early endosomes in mRNA intracellular distribution. Here, we determine the cryo-EM structure of human FERRY. It reveals a unique clamp-like architecture that bears no resemblance to any known structure of Rab effectors. A combination of functional and mutational studies...

During the final stages of oocyte growth, transcription ceases only to resume following fertilization. During this cessation, the oocyte and the embryo can only use stores mRNAs to synthesize new products, meaning the storage of maternal mRNAs is critical for generating haploid eggs through meiosis and for early embryonic development. Membraneless...

Methyl-5-uridine (m5U) is one of the most abundant RNA modifications found in cytosolic tRNA. tRNA methyltransferase 2 homolog A (hTRMT2A) is the dedicated mammalian enzyme of m5U conversion at tRNA position 54. However, its RNA binding specificity and functional role in the cell are not well understood. Here we dissected structural and sequence re...

Technical and methodological advances enable to apply crosslinking mass spectrometry (XL-MS) for the identification of DNA and RNA binding sites within proteins in vitro. The use of chemical crosslinking agents and incorporation of photoactivatable nucleotides increases crosslinking efficiencies broadening the applicability of XL-MS to in vivo stud...

Full-grown oocytes are transcriptionally silent and must stably maintain the messenger RNAs (mRNAs) needed for oocyte meiotic maturation and early embryonic development. However, where and how mammalian oocytes store maternal mRNAs is unclear. Here, we report that mammalian oocytes accumulate mRNAs in a mitochondria-associated ribonucleoprotein dom...

The eukaryotic tRNA guanine transglycosylase (TGT) is an RNA modifying enzyme incorporating queuine, a hypermodified guanine derivative, into the tRNAsAsp,Asn,His,Tyr. While both subunits of the functional heterodimer have been crystallized individually, much of our understanding of its dimer interface or recognition of a target RNA have been infer...

Long-range mRNA transport is crucial for the spatio-temporal regulation of gene expression, and its malfunction is linked to neurological disorders. The pentameric FERRY Rab5 effector complex is the molecular link between mRNA and the early endosome in mRNA intracellular distribution. Here, we determine the cryo-EM structure of the human FERRY comp...

The mechanisms by which viruses hijack their host's genetic machinery are of enormous current interest. One mechanism is adenosine diphosphate (ADP) ribosylation, where ADP-ribosyltransferases (ARTs) transfer an ADP-ribose fragment from the ubiquitous coenzyme nicotinamide adenine dinucleotide (NAD) to acceptor proteins. When bacteriophage T4 infec...

The mechanisms by which viruses hijack their host’s genetic machinery are of enormous current interest. One mechanism is adenosine diphosphate (ADP) ribosylation, where ADP-ribosyltransferases (ARTs) transfer an ADP-ribose fragment from the ubiquitous coenzyme nicotinamide adenine dinucleotide (NAD) to acceptor proteins. When bacteriophage T4 infec...

TrmB belongs to the class I S-adenosylmethionine (SAM)-dependent methyltransferases (MTases) and introduces a methyl group to guanine at position 7 (m7G) in tRNA. In tRNAs m7G is most frequently found at position 46 in the variable loop and forms a tertiary base pair with C13 and U22, introducing a positive charge at G46. The TrmB/Trm8 enzyme famil...

Protein–DNA interactions are key to the functionality and stability of the genome. Identification and mapping of protein–DNA interaction interfaces and sites is crucial for understanding DNA-dependent processes. Here, we present a workflow that allows mass spectrometric (MS) identification of proteins in direct contact with DNA in reconstituted and...

Dnmt2 methylates cytosine at position 38 of tRNAAsp in a variety of eukaryotic organisms. A correlation between the presence of the hypermodified nucleoside queuosine (Q) at position 34 of tRNAAsp and the Dnmt2 dependent C38 methylation was recently found in vivo for S. pombe and D. discoideum. We demonstrate a direct effect of the Q-modification o...