Brat is a Miranda cargo protein that promotes neuronal differentiation and inhibits neuroblast self-renewal.
An important question in stem cell biology is how a cell decides to self-renew or differentiate. Drosophila neuroblasts divide asymmetrically to self-renew and generate differentiating progeny called GMCs. Here, we report that the Brain tumor (Brat) translation repressor is partitioned into GMCs via direct interaction with the Miranda scaffolding protein. In brat mutants, another Miranda cargo protein (Prospero) is not partitioned into GMCs, GMCs fail to downregulate neuroblast gene expression, and there is a massive increase in neuroblast numbers. Single neuroblast clones lacking Prospero have a similar phenotype. We conclude that Brat suppresses neuroblast stem cell self-renewal and promotes neuronal differentiation.
Institutes of Neuroscience and Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, 97403, USA.
Cheng-Yu
CY
Lee
Brian D
BD
Wilkinson
Sarah E
SE
Siegrist
Robin P
RP
Wharton
Chris Q
CQ
Doe
D000818:Animals; D002452:Cell Count; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C107613:Mira protein, Drosophila; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C412783:brat protein, Drosophila; C073099:pros protein, Drosophila