Pou3f transcription factor expression during embryonic development highlights distinct pou3f3 and pou3f4 localization in the Xenopus laevis kidney

Abstract

The POU (Pit-Oct-Unc) genes encode a large transcription factor family comprising 6 classes (pou1f to pou6f ) involved in many developmental processes, such as cell commitment and differentiation. The pou3f class contains four members (pou3f1, pou3f2, pou3f3, pou3f4) characterized by expression in ectodermal tissue derivatives, such as nervous system and otic vesicle, during mammalian development. In order to obtain insights into the potential conservation of this class of transcription factors in vertebrates, we carried out a phylogenetic analysis and a comprehensive comparative study of pou3f expression in the frog Xenopus laevis. All vertebrates examined possessed members of the four pou3f subfamilies, excepting the zebrafish, which lacked a pou3f4 gene. Whole mount in situ hybridization and real-time quantitative polymerase chain reaction (RT-qPCR) analyses revealed that Xenopus pou3f genes were expressed in the forming neural tube and their expression was maintained in the brain, mostly in the dorsal part, at tailbud stages. The pou3f2, pou3f3, and pou3f4 genes were also expressed in the developing otic vesicle, and pou3f1 in some cells of the epidermis. Besides ectodermal derivatives, pou3f3 and pou3f4 were expressed in the developing kidney. Their expression started at the early tailbud stage in the pronephric anlage and partly overlapped. In the mature pronephric tubule, pou3f3 was restricted to the intermediate tubule, while pou3f4 was also expressed in the distal and connecting tubule. Together, our results highlight a significant conservation of pou3f gene expression in vertebrates and indicate that they may have distinct but also redundant functions during neural and renal development.

Pairing your Sox: Identification of Sox11 partner proteins and interaction domains in the developing neural plate

“…We also confirmed coexpression by performing whole mount in situ hybridization (WISH) analysis of stage 12 (late gastrula) and stage 14 (neurula) Xenopus embryos demonstrating that sox11 expression overlaps with ngn2 anpou3f2 ( Figure S2). In line with our WISH data, previous research shows pou3f2 expression is not detectable at stage 12 by WISH due to low transcript levels, but is visible at stage 14 in the anterior neural plate (37).…”

“…We also show that xSox11 interacts with xPou3f2 (also known as Brn2 or Oct7), however, this relationship is not well defined in Xenopus neural plate development and has various expression patterns and functions across species. Pou3f2 is robustly expressed in stage 14 neurulae but is not detectable in stage 12 gastrulae ( Figure SA1) (37). In rat neural precursor cells, Pou3f2 co-localizes with progenitor cell markers and is downregulated upon differentiation (44).…”

Research progress of the transcription factor Brn4 (Review)

“…In addition, Brn4 has been detected in the embryonic pancreas and adult glucagon cells (23,24). A previous study investigating the role of the POU3 gene during development in Xenopus laevis found that Brn4 was expressed in the embryonic neural tube, brain, developmental ear vesicles, distal renal tubules and connective tubules (11). RNA sequencing results of the genome-wide analysis of 272 mouse cell and tissue types revealed the widespread expression of Brn4 during nervous system development, including within the neural crest, neuroectoderm, hypothalamus, pituitary, hippocampus and inner ear (5).…”

“…Brn1 is involved in the development of the central nervous system, and its loss-of-function mutations were identified to cause developmental delays, intellectual disability and impairments in language skills (10). It was also found to be expressed in the developing kidney (11). In previous studies, Brn1 knockout mice were discovered to have neurological defects, including locomotor and auditory impairments, but also a thicker ascending loop of the limb of Henle and decreased numbers of nephrons, thus resulting in renal failure and perinatal death (12,13).…”

X-linked Malformation Deafness: Neurodevelopmental Symptoms Are Common in Children With IP3 Malformation and Mutation in POU3F4

“…POU3F4 , along with the gene EPHA4 , is also important in spiral ganglion fasciculation in the spiral ligament and essential for correct ganglion innervation ( Coate et al 2012 ). It is also expressed in the developing brain and kidney ( Petersen et al 2008 ; Cosse-Etchepare et al 2018 ) although functional studies within these organs are lacking. Mutations within POU3F4 lead to a severe mixed or sensorineural hearing loss, which in most patients affect all audiometric frequencies and can be progressive ( Petersen et al 2008 ).…”