biostudies-literatureHu YInternational School of MedicineUniversity of Toronto Open FellowshipsCanadian Institutes of Health ResearchZhejiang UniversityCIHRiyaf015https://www.ebi.ac.uk/biostudies/studies/S-EPMC11912871biostudies-literatureUnknown229(3)The Drosophila TRIM-NHL RNA-binding protein (RBP), MEI-P26, has previously been shown to suppress tumor formation in the germline. Here we show that, in the Drosophila larval central brain, cell-type-specific expression of MEI-P26 plays a vital role in regulating neural development. MEI-P26 and another TRIM-NHL RBP, Brain tumor (BRAT), have distinct expression patterns in Type I neuroblast (NB) lineages: While both proteins are expressed in NBs, BRAT is expressed in ganglion mother cells (GMCs) but not neurons, whereas MEI-P26 is expressed in neurons but not GMCs. Knockdown of MEI-P26 leads to re-expression of the stem cell marker Deadpan (DPN) and over-production of neurons. In contrast, ectopically expressed MEI-P26 reduces NB lineage size by repressing division of GMCs, resulting in redGeneticsThe TRIM-NHL RNA-binding protein MEI-P26 modulates the size of Drosophila Type I neuroblast lineages.PMC11912871PJT-190124Q23019PJT-159702Yang XHu YLipshitz HDfalseThe TRIM-NHL RNA-binding protein MEI-P26 modulates the size of Drosophila Type I neuroblast lineages.The Drosophila TRIM-NHL RNA-binding protein (RBP), MEI-P26, has previously been shown to suppress tumor formation in the germline. Here we show that, in the Drosophila larval central brain, cell-type-specific expression of MEI-P26 plays a vital role in regulating neural development. MEI-P26 and another TRIM-NHL RBP, Brain tumor (BRAT), have distinct expression patterns in Type I neuroblast (NB) lineages: While both proteins are expressed in NBs, BRAT is expressed in ganglion mother cells (GMCs) but not neurons, whereas MEI-P26 is expressed in neurons but not GMCs. Knockdown of MEI-P26 leads to re-expression of the stem cell marker Deadpan (DPN) and over-production of neurons. In contrast, ectopically expressed MEI-P26 reduces NB lineage size by repressing division of GMCs, resulting in red2025-01-01T00:00:00Z2025 Mar2026-07-07T03:17:25.897Z2025-04-05T12:38:56.954ZS-EPMC119128713985426710.1093/genetics/iyaf015