Biology subjects

Perroud, P.-F.

Publications and source records attributed to Perroud, P.-F..

3 recordsLinked to original sources

bioRxiv2023

Establishing CRISPR-Cas9 in the sexually dimorphic moss, Ceratodon purpureus.

The development of CRISPR technologies provides a powerful tool for understanding the evolution and functionality of essential biological processes. Here we demonstrate successful CRISPR-Cas9 genome editing in the dioecious moss species, Ceratodon purpureus. Using an existing selection system from the distantly related hermaphroditic moss, Physcomitrium patens, we generated knock-outs of the APT reporter gene by employing CRISPR targeted mutagenesis under expression of native U6 snRNA promoters. Next, we used the native homology-directed repair (HDR) pathway, combined with CRISPR-Cas9, to knock-in two reporter genes under expression of an endogenous RPS5A promoter in a newly developed landing site in C. purpureus. Our results show that the molecular tools developed in P. patens can be extended to other mosses across this ecologically important and developmentally variable group. These findings pave the way for precise and powerful experiments aimed at identifying the genetic basis of key functional variation within the bryophytes and between the bryophytes and other land plants. Significance StatementWe have developed CRISPR-Cas9 genome editing tools and protocols for the sexually dimorphic moss, Ceratodon purpureus to generate gene knock-outs and knock-ins within targeted loci. This work facilitates future functional genomic experiments in this fast growing, haploid, dioecious system and suggests these tools will function across much of moss diversity.

molecular biology↗

bioRxiv2021

Calpain DEK1 acts as a developmental switch gatekeeping cell fate transitions

Calpains are cysteine proteases that control cell fate transitions. Although calpains are viewed as modulatory proteases displaying severe, pleiotropic phenotypes in eukaryotes, human calpain targets are also directed to the N-end rule degradatory pathway. Several of these destabilized targets are transcription factors, hinting at a gene regulatory role. Here, we analyze the gene regulatory networks of Physcomitrium patens and characterize the regulons that are deregulated in DEK1 calpain mutants. Predicted cleavage patterns of regulatory hierarchies in the five DEK1-controlled subnetworks are consistent with the genes pleiotropy and the regulatory role in cell fate transitions targeting a broad spectrum of functions. Network structure suggests DEK1-gated sequential transition between cell fates in 2D to 3D development. We anticipate that both our method combining phenotyping, transcriptomics and data science to dissect phenotypic traits and our model explaining the calpains role as a switch gatekeeping cell fate transitions will inform biology beyond plant development.

developmental biology↗

bioRxiv2019

Characterization of evolutionarily conserved key players affecting eukaryotic flagellar motility and fertility using a moss model

Defects in flagella/cilia are often associated with infertility and disease. Motile male gametes (sperm cells) with flagella are an ancestral eukaryotic trait that has been lost in several lineages, for example in flowering plants. Here, we made use of a phenotypic male fertility difference between two moss (Physcomitrella patens) strains to explore spermatozoid function. We compare genetic and epigenetic variation as well as expression profiles between the Gransden and Reute strain to identify a set of genes associated with moss male infertility. Defects in mammal and algal homologs of these genes coincide with a loss of fertility, demonstrating the evolutionary conservation of flagellar function related to male fertility across kingdoms. As a proof of principle, we generated a loss-of-function mutant of a coiled-coil domain containing 39 (ccdc39) gene that is part of the flagellar hydin network. Indeed, the Ppccdc39 mutant resembles the male infertile Gransden strain phenotype. Potentially, several somatic (epi-)mutations occurred during prolonged vegetative propagation of P. patens Gransden, causing regulatory differences of e.g. the homeodomain transcription factor BELL1. Probably these somatic changes are causative for the observed male fertility. We propose that P. patens spermatozoids might be employed as an easily accessible system to study male infertility of human and animals.

plant biology↗