Biology subjects

Mann, F. G.

Publications and source records attributed to Mann, F. G..

3 recordsLinked to original sources

bioRxiv2021

Hox genes regulate asexual reproductive behavior and tissue segmentation in adult animals

Hox genes are highly conserved transcription factors renowned for their roles in the segmental patterning of the embryonic anterior-posterior (A/P) axis1. Emerging evidence for Hox gene expression and function in postnatally derived structures has fueled interest in their additional roles beyond embryogenesis2,3. We report novel functions for Hox genes in A/P adult tissue segmentation and transverse fission behavior underlying asexual reproduction in the planarian flatworm, Schmidtea mediterranea. Silencing of each of the planarian Hox family members identified 5 Hox genes required for asexual reproduction. Among these, silencing of hox3 genes resulted in supernumerary segments, while silencing of post2b eliminated segmentation altogether. The opposing roles of hox3 and post2b in segmentation are paralleled in their respective regulation of fission behavior. Silencing of hox3 increased the frequency of fission behavior initiation, while silencing of post2b eliminated fission behavior entirely. Furthermore, we identified a network of downstream effector genes mediating Hox gene regulation of asexual reproduction, thereby providing insight into their respective mechanisms of action. Our study establishes postembryonic roles for Hox genes in regulating the emergence of tissue segmentation and specific behaviors associated with asexual reproduction in adult animals.

developmental biology↗

bioRxiv2020

Decellularization enables functional analysis of ECM remodeling in planarian regeneration

The extracellular matrix (ECM) is a three-dimensional network of macromolecules that provides a microenvironment capable of supporting and regulating cell functions. However, only a few research organisms are available for the systematic dissection of the composition and functions of the ECM, particularly during regeneration. We utilized a free-living flatworm Schmidtea mediterranea to develop an integrative approach consisting of decellularization, proteomics, and RNA-interference (RNAi) to characterize and investigate ECM functions during tissue homeostasis and regeneration. High-quality ECM was isolated from planarians, and its matrisome profile was characterized by LC-MS/MS. The functions of identified ECM components were interrogated using RNAi. Using this approach, we discovered that heparan sulfate proteoglycan and kyphoscoliosis peptidase are essential for both tissue homeostasis and regeneration. Our strategy provides a robust experimental approach for identifying novel ECM components involved in regeneration that might not be discovered bioinformatically.

developmental biology↗

bioRxiv2020

Identification of rare transient somatic cell states induced by injury and required for whole-body regeneration

Regeneration requires functional coordination of stem cells, their progeny, and differentiated cells. Past studies have focused on regulation of stem cell identity and proliferation near to the wound-site, but less is known about contributions made by differentiated cells distant to the injury. Here, we present a comprehensive atlas of whole-body regeneration over time and identify rare, transient, somatic cell states induced by injury and required for regeneration. To characterize amputation-specific signaling across a whole animal, 299,998 single-cell transcriptomes were captured from planarian tissue fragments competent and incompetent to regenerate. Amputation-specific cell states were rare, non-uniformly distributed across tissues, and particularly enriched in muscle (mesoderm), epidermis (ectoderm), and intestine (endoderm). Moreover, RNAi-mediated knockdown of genes up-regulated in amputation-specific cell states drastically reduced regenerative capacity. These results identify novel cell states and molecules required for whole-body regeneration and indicate that regenerative capacity requires transcriptional plasticity in a rare subset of differentiated cells.

developmental biology↗