Dillon Noah R, Manning Laurina, Hirono Keiko, Doe Chris Q
Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403.
bioRxiv. 2023 Nov 3:2023.11.02.565340. doi: 10.1101/2023.11.02.565340.
An open question in neurobiology is how diverse neuron cell types are generated from a small number of neural stem cells. In the larval central brain, there are eight bilateral Type 2 neuroblast (T2NB) lineages that express a suite of early temporal factors followed by a different set of late temporal factors and generate the majority of the central complex (CX) neurons. The early-to-late switch is triggered by the orphan nuclear hormone receptor Seven-up (Svp), yet little is known about this Svp-dependent switch in specifying CX neuron identities. Here, we (i) birthdate the CX neurons P-EN and P-FN (early and late, respectively); (ii) show that Svp is transiently expressed in all early T2NBs; and (iii) show that loss of Svp expands the population of early born P-EN neurons at the expense of late born P-FN neurons. Furthermore, in the absence of Svp, T2NBs fail decommissioning and abnormally extend their lineage into week-old adults. We conclude that Svp is required to specify CX neuron identity, as well as to initiate T2NB decommissioning.
神经生物学中的一个开放性问题是，如何从少量神经干细胞产生多种类型的神经元细胞。在幼虫的中枢脑中，有八个双侧2型神经母细胞（T2NB）谱系，它们表达一组早期时间因子，随后是另一组不同的晚期时间因子，并产生大部分中央复合体（CX）神经元。从早期到晚期的转变由孤儿核激素受体Seven-up（Svp）触发，但对于这种依赖Svp的转变在确定CX神经元身份方面的了解甚少。在这里，我们（i）确定了CX神经元P-EN和P-FN的出生日期（分别为早期和晚期）；（ii）表明Svp在所有早期T2NB中短暂表达；（iii）表明Svp的缺失以牺牲晚期出生的P-FN神经元为代价，扩大了早期出生的P-EN神经元的数量。此外，在没有Svp的情况下，T2NB无法退役，并异常地将其谱系延伸到一周大的成虫中。我们得出结论，Svp对于确定CX神经元身份以及启动T2NB退役是必需的。
