Search PubMed⌕ Search

Biomedical subjects

Jonathan M Mudge

Publications and source records attributed to Jonathan M Mudge.

4 recordsLinked to original sources

Expanding the human proteome with microproteins and peptideins.

A major scientific drive is to characterize the protein-coding genome, which is a primary basis for studying human health. But the fundamental question remains of what has been missed in previous analyses. Over the past decade, the translation of non-canonical open reading frames (ncORFs) has been observed across human cell types and disease states1-3, with major implications for biomedical science. However, a key gap in knowledge has been which ncORFs produce small microproteins or alternative protein molecules that contribute to the human proteome. Here we report the collaborative efforts of the TransCODE Consortium4 to produce a consensus landscape of protein-level evidence for ncORFs. We show that about 25% of a set of 7,264 ncORFs gives rise to detectable peptides in a large-scale analysis of 95,520 proteomics experiments. We develop an annotation framework for ncORF-encoded microproteins as human proteins and codify the new conceptual model of 'peptideins' as microproteins that have indeterminate potential as functional proteins. To probe the biological implications of peptideins, we create an evolutionary analysis approach, termed ORF relative branch length (ORBL), and determine that evolutionary constraint is common and associates with observation of ncORF-derived peptides. We then characterize a pan-essential cellular phenotype for one peptidein from the OLMALINC long non-coding RNA. Overall, we generate public research tools supported by GENCODE and PeptideAtlas and advance biomedical discovery for understudied components of the human proteome.

Humans↗

Programmed ribosomal frameshifting during PLEKHM2 mRNA decoding generates a constitutively active proteoform that supports myocardial function.

Programmed ribosomal frameshifting is a process where a proportion of ribosomes change their reading frame on an mRNA. While frameshifting is commonly used by viruses, very few phylogenetically conserved examples are known in nuclear encoded genes. Here, we report a +1 frameshifting event during decoding of the human gene PLEKHM2 that provides access to a second internally overlapping ORF. The new carboxyl-terminal domain of this frameshift protein forms an α helix, which relieves PLEKHM2 from autoinhibition and allows it to move to the tips of cells without activation by ARL8. Reintroducing both the canonically translated and frameshifted protein are necessary to restore normal contractile function of PLEKHM2 knockout cardiomyocytes, demonstrating the necessity of frameshifting for normal cardiac activity.

Frameshifting, Ribosomal↗

High-quality peptide evidence for annotating non-canonical open reading frames as human proteins.

A major scientific drive is to characterize the protein-coding genome as it provides the primary basis for the study of human health. But the fundamental question remains: what has been missed in prior genomic analyses? Over the past decade, the translation of non-canonical open reading frames (ncORFs) has been observed across human cell types and disease states, with major implications for proteomics, genomics, and clinical science. However, the impact of ncORFs has been limited by the absence of a large-scale understanding of their contribution to the human proteome. Here, we report the collaborative efforts of stakeholders in proteomics, immunopeptidomics, Ribo-seq ORF discovery, and gene annotation, to produce a consensus landscape of protein-level evidence for ncORFs. We show that at least 25% of a set of 7,264 ncORFs give rise to translated gene products, yielding over 3,000 peptides in a pan-proteome analysis encompassing 3.8 billion mass spectra from 95,520 experiments. With these data, we developed an annotation framework for ncORFs and created public tools for researchers through GENCODE and PeptideAtlas. This work will provide a platform to advance ncORF-derived proteins in biomedical discovery and, beyond humans, diverse animals and plants where ncORFs are similarly observed.

GENCODE↗

Neocentromeres in 15q24-26 map to duplicons which flanked an ancestral centromere in 15q25.

The existence of latent centromeres has been proposed as a possible explanation for the ectopic emergence of neocentromeres in humans. This hypothesis predicts an association between the position of neocentromeres and the position of ancient centromeres inactivated during karyotypic evolution. Human chromosomal region 15q24-26 is one of several hotspots where multiple cases of neocentromere emergence have been reported, and it harbors a high density of chromosome-specific duplicons, rearrangements of which have been implicated as a susceptibility factor for panic and phobic disorders with joint laxity. We investigated the evolutionary history of this region in primates and found that it contains the site of an ancestral centromere which became inactivated about 25 million years ago, after great apes/Old World monkeys diverged. This inactivation has followed a noncentromeric chromosomal fission of an ancestral chromosome which gave rise to phylogenetic chromosomes XIV and XV in human and great apes. Detailed mapping of the ancient centromere and two neocentromeres in 15q24-26 has established that the neocentromere domains map approximately 8 Mb proximal and 1.5 Mb distal of the ancestral centromeric region, but that all three map within 500 kb of duplicons, copies of which flank the centromere in Old World Monkey species. This suggests that the association between neocentromere and ancestral centromere position on this chromosome may be due to the persistence of recombinogenic duplications accrued within the ancient pericentromere, rather than the retention of "centromere-competent" sequences per se. The high frequency of neocentromere emergence in the 15q24-26 region and the high density of clinically important duplicons are, therefore, understandable in the light of the evolutionary history of this region.

Animals↗