Mxc, a Drosophila homolog of mental retardation-associated gene NPAT, maintains neural stem cell fate

Abstract

Background Mental retardation is a complex neurodevelopmental disorder. NPAT, a component of the histone locus body (HLB), has been implicated as a candidate gene for mental retardation, with a mechanism yet to be elucidated. Results We identified that mxc, the Drosophila ortholog of NPAT, is required for the development of nervous system. Knockdown of mxc resulted in a massive loss of neurons and locomotion dysfunction in adult flies. In the mxc mutant or RNAi knockdown larval brains, the neuroblast (NB, also known as neural stem cell) cell fate is prematurely terminated and its proliferation potential is impeded concurrent with the blocking of the differentiation process of ganglion mother cells (GMCs). A reduction of transcription levels of histone genes was shown in mxc knockdown larval brains, accompanied by DNA double-strand breaks (DSBs). The subsidence of histone transcription levels leads to prematurely termination of NB cell fate and blockage of the GMC differentiation process. Our data also show that the increase in autophagy induced by mxc knockdown in NBs could be a defense mechanism in response to abnormal HLB assembly and premature termination of NB cell fate. Conclusions Our study demonstrate that Mxc plays a critical role in maintaining neural stem cell fate and GMC differentiation in the Drosophila larval brain. This discovery may shed light on the understanding of the pathogenesis of NPAT-related mental retardation in humans.

Co-dependent regulation of p-BRAF and potassium channel KCNMA1 levels drives glioma progression

“…Slo cDNA encoding aa 636 to 816 was cloned into a pGEX-4T-1 expression vector. The antigen was bacterially produced, and the antibody raised in rabbits according to the published protocol [ 39 ].…”

“…For cell immunostaining, cells on slides were fixed for 15 min in PBS with 4% paraformaldehyde at room temperature. All samples were incubated with primary antibodies at 4 °C overnight, followed by washes and mixture of the secondary antibodies at room temperature for 2 h [ 39 , 40 ]. All commercial secondary antibodies used were from the Jackson Laboratory.…”

“…Samples were subjected to SDS-PAGE and transferred to a polyvinylidene fluoride membrane (Millipore #IPVH0001). Western blot assays were performed according to the published protocol [ 39 ]. Immunoreactive bands were visualized using Clinx ChemiScope.…”

“…A 7900HT fast real-time PCR system (Applied Biosystems) was used for quantitative RT-PCR. PCR was carried out using a Power SYBR Green PCR Mix Kit (Vazyme) in 96-well plates following published methods [ 39 ]. rp49 was used as an internal control for Drosophila brain samples and GAPDH for human samples.…”

Pipsqueak family genes dan/danr antagonize nuclear Pros and prevent premature decommission of neural stem cells in Drosophila third instar larval brains

“…The observation of smaller lineages of dan/danr NB clones prompted us to examine Pros location in these NBs since nuclear Pros has been considered as a typical signal for the termination of NB cell fate (Lai and Doe 2014;Wu et al 2019;Sang et al 2022). Nuclear Pros was indeed observed in the dan/danr NBs (Figures 2A -C).…”