Selected Grantee Publications
Two Neuronal Peptides Encoded from a Single Transcript Regulate Mitochondrial Complex III in Drosophila
Bosch et al., eLife. 2022.
https://www.doi.org/10.7554/eLife.82709
Transcripts with small open-reading frames (smORFs) are underrepresented in genome annotations. Functions of peptides encoded by smORFs are poorly understood. The investigators systematically characterized human-conserved smORF genes in Drosophila and found two peptides, Sloth1 and Sloth2, that are highly expressed in neurons. They showed that Sloth1 and Sloth2 are paralogs with high sequence similarity but are not functionally redundant. Loss of either peptide resulted in lethality, impaired mitochondrial function, and neurodegeneration. This work suggests the value of phenotypic analysis of smORFs using Drosophila as a model. Supported by ORIP (R24OD019847), NHGRI, and NIGMS.
De Novo Variants in EMC1 Lead to Neurodevelopmental Delay and Cerebellar Degeneration and Affect Glial Function in Drosophila
Chung et al., Human Molecular Genetics. 2022.
https://www.doi.org/10.1093/hmg/ddac053
Variants in EMC1, which encodes a subunit of the endoplasmic reticulum (ER)–membrane protein complex (EMC), are associated with developmental delay in children. Functional consequences of these variants are poorly understood. The investigators identified de novo variants in EMC1 in three children affected by global developmental delay, hypotonia, seizures, visual impairment, and cerebellar atrophy. They demonstrated in Drosophila that these variants are loss-of-function alleles and lead to lethality when expressed in glia but not in neurons. This work suggests the causality of EMC variants in disease. Supported by ORIP (R24OD022005, R24OD031447), NINDS, and NICHD.
Rbbp4 Loss Disrupts Neural Progenitor Cell Cycle Regulation Independent of Rb and Leads to Tp53 Acetylation and Apoptosis
Schultz-Rogers et al., Developmental Dynamics. 2022.
https://www.doi.org/10.1002/dvdy.467
Retinoblastoma binding protein 4 (Rbbp4) is a component of transcription regulatory complexes that control cell cycle gene expression by cooperating with the Rb tumor suppressor to block cell cycle entry. The authors used genetic analysis to examine the interactions of Rbbp4, Rb, and Tp53 in zebrafish neural progenitor cell cycle regulation and survival. Rbbp4 is upregulated across the spectrum of human embryonal and glial brain cancers, and it is essential for zebrafish neurogenesis. Rbbp4 loss leads to apoptosis and γ-H2AX in the developing brain that is suppressed by tp53 knockdown or maternal zygotic deletion. Mutant retinal neural precursors accumulate in M phase and fail to initiate G0 gene expression. Rbbp4; Rb1 double mutants show an additive effect on the number of M phase cells. The study demonstrates that Rbbp4 is necessary for neural progenitor cell cycle progression and initiation of G0, independent of Rb, and suggests that Rbbp4 is required for cell cycle exit and contributes to neural progenitor survival. Supported by ORIP (R24OD020166) and NIGMS.
Allogeneic MHC‑Matched T‑Cell Receptor Α/Β‑Depleted Bone Marrow Transplants in SHIV‑Infected, ART‑Suppressed Mauritian Cynomolgus Macaques
Weinfurter et al., Scientific Reports. 2022.
https://www.doi.org/10.1038/s41598-022-16306-z
Allogeneic hematopoietic stem cell transplants are effective in reducing HIV reservoirs following antiretroviral therapy (ART). A better understanding of this mechanism could enable the development of safer and more efficacious HIV treatment regimens. In this study, the researchers used a Mauritian cynomolgus macaque model to study the effects of allogeneic major histocompatibility complex–matched α/β T cell–depleted bone marrow cell transplantation following infection with simian–human immunodeficiency virus (SHIV). The macaques began ART 6 to 16 weeks post-infection. In three of the four macaques, SHIV DNA was undetectable in blood but persisted in other tissues. These results suggest that extended ART likely is needed to eradicate the HIV reservoir following transplantation. In future studies, full donor engraftment should be balanced with suppression of graft-versus-host disease. Supported by ORIP (P51OD011106, R24OD021322), and NCI.