Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.08.09.669486

rapunzel5 is necessary for normal hematopoietic development in zebrafish

Thapa, S.·Dowell, W.·Harris, E.·Stachura, D. L.
View original source ↗Export metadata ↓

Abstract

The molecular mechanisms regulating the highly complex process of hematopoiesis in vertebrates is still enigmatic. This system begins with the controlled differentiation of adult hematopoietic stem and progenitor cells (HSPCs), which can proliferate and generate all types of mature blood cells. Identifying the underlying factors and mechanisms that allow HSPCs to differentiate and proliferate is an essential issue in stem cell biology and tissue homeostasis; disruptions in these processes can cause severe diseases. A transcriptomic screen of hematopoietic-supportive zebrafish stromal tissues identified rapunzel5 (rpz5) was likely involved in vertebrate hematopoiesis. We performed loss-of-function experiments in zebrafish embryos at the one-cell-stage with morpholinos to determine if blood cell production was affected by rpz5. rpz5 knockdown resulted in reduced amounts of red blood cells, myeloid cells, and thrombocytes, and adding back exogenous rpz5 rescued these deficiencies. Further analysis with methylcellulose assays indicated that there was also a significant reduction in HSPCs following rpz5 reduction. Together, these findings suggest that zebrafish rpz5 is essential for normal formation, differentiation, and proliferation of HSPCs, specifically down the erythroid and myeloid pathway. Fully understanding the roles of novel genes such as rpz5 is essential for understanding the evolution of vertebrate hematopoiesis and for treating hematological diseases in the future.

Explore related subjects

geneticsPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Thapa, S., Dowell, W., Harris, E., Stachura, D. L.. 2025-08-12. rapunzel5 is necessary for normal hematopoietic development in zebrafish. https://doi.org/10.1101/2025.08.09.669486

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

The histone demethylase Kdm5 and the ARGONAUTE proteins Piwi and Aubergine regulate female abdominal pigmentation in Drosophila melanogaster

Insect pigmentation is an ecologically critical trait influencing many physiological processes. In Drosophila melanogaster, abdominal pigmentation is sexually dimorphic: males have fully pigmented posterior segments, while females exhibit a posterior melanin stripe. Pigmentation relies on the expression of pigmentation genes that encode enzymes involved in pigment synthesis. These genes are tightly regulated during pupal and young adult stages. To expand the gene regulatory network of pigmentation genes, we conducted an RNAi screen using the yellow-Gal4 driver, expressed during the pupal stage in abdominal epidermis. One of the candidates from this screen, Kdm5, encodes a histone demethylase erasing the H3K4me3 histone mark catalyzed by the histone methyl-transferase Trithorax (Trx). We show that Kdm5 down-regulation reduces abdominal pigmentation, mimicking trx down-regulation. Kdm5 activates melanin production through regulation of the pigmentation gene tan. Transcriptomic analyses reveal that Kdm5 and Trx share many targets in pupal abdominal epidermis, including piRNA pathway components such as piwi and aubergine. These piRNA components, originally associated with transposon silencing in the germline, also function in some somatic tissues such as the nervous system, the fat body or the gut. We demonstrate that Piwi and Aubergine participate in female abdominal pigmentation establishment, without evident piRNA production. We also show that Kdm5 and Piwi act not only in pupal abdominal epidermis but also in pupal fat body. This study therefore expands the regulatory network of pigmentation genes. It identifies a new somatic function for Kdm5 and Piwi and reveals a role for pupal fat body in female abdominal pigmentation regulation.

genetics↗
bioRxiv2026

Genetic diversity within and between polyploid sugarcane (Saccharum spp.) families obtained via caryopsis using microsatellite markers and multicategory model

Genetic diversity analyses are essential for sugarcane (Saccharum spp.) breeding programs. Crossbreeding, based on genetic distances between parental plants, is a tool used to increase genetic variability and enhance plant selection; however, quantifying variation in highly polyploid species remains a challenge. The present study aimed to evaluate the diversity within and between 12 families of sugarcane derived from caryopses, analyzing 120 individual seedlings arranged in an augmented block design. Genotyping was performed using primers for 16 microsatellite loci, five simple sequence repeat (SSR) loci, and 11 expressed sequence tag-SSR (EST-SSR) loci. To accurately account for polyploidy, similarity calculations were performed using Bruvos distances among individuals and RST distances among the families. Analysis of molecular variance (AMOVA) indicated that most of the genetic variability was within families (72%), with only 28% found between them. This high level of intra-family variation demonstrates that a significant reservoir of genetic diversity remains available within the crosses. The highest genetic similarity was observed between the families RB986952 x RB986960 and RB036122 x RB03611, whereas the lowest genetic similarity was observed between the families RB97319 x RB966928 and RB106802 x RB855036. Although the evaluated families shared high genetic similarity, the pronounced genetic variation within them demonstrates a robust recombination potential, indicating that the genetic basis of sugarcane can be better explored using the high variability that already exists in the selection of desirable morpho-agronomic characteristics within the families. Furthermore, this study highlights the importance of using appropriate distances for diversity studies with codominant markers, such as microsatellites, in polyploid species.

genetics↗
bioRxiv2026

Optimizing DNA extraction from environmentally degraded bone samples for molecular identification of cetacean species

Molecular identification of cetacean bone remains can be limited by DNA degradation and the presence of PCR inhibitors. Here, we present an optimized DNA extraction protocol based on a total demineralization method for environmentally exposed cetacean bones. The protocol uses 100 mg of bone powder, 24 h digestion with EDTA, N-lauroylsarcosine, and proteinase K, followed by a modified silica-column purification. Nine environmentally degraded bone samples representing eight individuals were processed. DNA concentrations ranged from 7.3 to 57.1 ng/uL (mean SD = 25.91- 13.91 ng/uL). The mitochondrial cytochrome b gene was successfully amplified from all samples using conventional PCR, and five samples (55.6%) yielded sequences suitable for downstream analysis. BLASTn identified Balaenoptera physalus as the closest database match for all recovered sequences, and phylogenetic analysis further supported their association with B. physalus reference sequences. These results demonstrate that the proposed protocol provides a practical approach for recovering amplifiable and molecularly informative mitochondrial DNA from environmentally degraded cetacean bone material, facilitating molecular identification from challenging skeletal remains.

genetics↗