Biology subjects

Kircher, B. K.

Publications and source records attributed to Kircher, B. K..

3 recordsLinked to original sources

bioRxiv2025

Oogenesis and germinal bed morphology of the brown anole (A. sagrei)

BackgroundThe brown anole is a model species of the genus Anolis, a squamate (encompassing lizards and snakes) group widely studied in evolutionary, behavioral, and developmental biology. Full genome annotation, the establishment of gene editing techniques, and comprehensive description of reproductive tract morphology and embryogenesis in this species, has laid the foundation for functional studies. However, analysis of brown anole oogenesis is still required and vital to optimize genome modification, mutant line establishment, and analyses of the evolution of reproductive developmental mechanisms. ResultsHere, we characterize ovary morphology and gametogenesis in the female brown anole, A. sagrei using brightfield imaging, microCT, histology staining, electron microscopy, and confocal imaging. We define 10 stages of oocyte maturation which commences inside the oogonial nest within the germinal bed and concludes with the mature follicle ready to ovulate based on follicle size, yolk-acquisition, and follicular, cellular, and basement membrane architecture. ConclusionsWe describe the complete oogenesis of the brown anole in 10 stages and report that oogenesis is highly conserved within iguanids, a suborder of lizards. With our staging framework, we lay the foundation for functional studies of oogenesis and optimized gene-editing.

developmental biology↗

bioRxiv2025

Poly(A) probe HCR RNA-FISH specifically marks pyriform nurse cells in the brown anole lizard ovary

Hybridization chain reaction RNA-fluorescent in situ hybridization (HCR RNA-FISH) is a powerful and increasingly used method for visualizing gene expression in cells and tissues. A probe set against polyadenylated RNA (poly(A)) is often used as a positive control for RNA integrity and staining quality. While optimizing this technique in the ovary of the brown anole lizard (Anolis sagrei), we found that the poly(A) probe produced a strikingly specific and intense signal in pyriform cells, a specialized lizard-specific nurse cell type. This staining pattern was found in both whole-mount samples and paraffin sections, suggesting that poly(A) signal intensity can serve as a robust molecular marker for this cell type. The specific and robust signal facilitated segmentation of volumetric data to create the first 3D models of pyriform cells and quantify their sphericity. We also observed unusually diffuse DAPI staining in pyriform cell nuclei, distinguishing them from surrounding granulosa cells, pointing to possible differences in chromatin structure or nuclear organization. Together, these findings highlight the potential of poly(A) probes used in HCR RNA-FISH not only as a technical control, but also as a tool to selectively label specific cell types with high transcriptional activity or storage of abundant poly(A) transcripts.

developmental biology↗

bioRxiv2024

Pre-oviposition development of the brown anole (Anolis sagrei)

The brown anole, Anolis sagrei, has emerged as a representative squamate species during the past several decades. Novel functional tools have been established to manipulate embryogenesis through genome editing or the introduction of small molecule inhibitors, and their effective use requires a thorough understanding of early anole embryogenesis. To enable precise and reproducible staging of anole embryos, we need knowledge of the progression of anole embryogenesis and morphogenesis. While post-oviposition development has been described, the pre-oviposition period remains to be explored. Here, we provide the first staging series of pre-oviposition development for the brown anole. Analysing the follicles and embryos through brightfield imaging, SEM, STEM, histology, and DAPI staining, we define 26 distinct developmental stages. Our dataset reveals that peri-gastrulation morphogenesis up to the initiation of neurulation diverges significantly from chicken, the common representative model of reptile embryogenesis. Furthermore, we followed heart development, neural crest cell migration and central nervous system development through immunofluorescence analyses and provide new comparative insights into the morphogenesis of each of these organ systems over time. Our work establishes the brown anole as a squamate model organism for cross clade evolutionary studies of early embryogenesis.

developmental biology↗