Project description:NGPS is a method for de-novo, full-length protein sequencing in high throughput. The method is based on cleavage of the protein at semi-random sites by microwave-assisted acid hydrolysis (MAAH), enrichment of LC-MS/MS amenable peptides from the hydrolysate by solid-phase-extraction, LC-MS/MS analysis, de-novo long peptide tag sequencing of resulting peptides and assembly of peptide tags into consensus contigs.
Project description:A core computational challenge in the analysis of mass spectrometry data is the de novo sequencing problem, in which the generating amino acid sequence is inferred directly from an observed fragmentation spectrum without the use of a sequence database. Recently, deep learning models have made significant advances in de novo sequencing by learning from massive datasets of high confidence labeled mass spectra. However, these methods are primarily designed for data-dependent acquisition (DDA) experiments. Over the past decade, the field of mass spectrometry has been moving toward using data-independent acquisition (DIA) protocols for the analysis of complex proteomic samples due to their superior specificity and reproducibility.
Hence, we present a new de novo sequencing model called Cascadia, which uses a transformer architecture to handle the more complex data generated by DIA protocols. In comparisons with existing approaches for de novo sequencing of DIA data, Cascadia achieves improved performance across a range of instruments and experimental protocols. Additionally, we demonstrate Cascadia’s ability to accurately discover de novo coding variants and peptides from the variable region of antibodies.
Project description:We developed an extraction-free qPCR assay to identify Omicron BA.1 cases and verified lineage by sequencing. We find that BA.2 variants show almost twice the viral load (Ct) compared to both BA.1 as well as Delta variants.
Project description:To identify cooperating lesions in de novo and therapy-related acute myeloid leukemia (t-AML) with translocation t(9;11)(p22;q23) we performed high-resolution SNP-array profiling on 40 leukemia samples [de novo: n=22; t-AML: n=16; unknown: n=2]. A mean of 1.73 copy number alterations (CNAs)/case were identified with no differences between de novo and t-AML cases. We identified a novel minimally deleted region (MDR) at 7q36.1-q36.2 partly overlapping with a MDR previously identified in core-binding factor AML; MLL3 was the only gene affected in both regions. In addition, a recurrent gain was found at 13q21.33-q22.1 harboring the potential oncogene KLF5. Sequence/expression analysis of selected candidate genes revealed deregulated EVI1 at high frequency (50%). Copy-neutral loss-of-heterozygosity (CN-LOH) was absent in the paired cohort Further analysis of the candidate genes might provide novel insights into the pathogenesis of t(9;11) AML