Biology subjects

Hattori, R. S.

Publications and source records attributed to Hattori, R. S..

3 recordsLinked to original sources

bioRxiv2024

De novo assembly and characterization of a highly degenerated ZW sex chromosome in the fish Megaleporinus macrocephalus

BackgroundMegaleporinus macrocephalus (piaucu) is a Neotropical fish within Characoidei that presents a well-established heteromorphic ZZ/ZW sex-determination system and thus, constitutes a good model for studying W and Z chromosomes in fishes. We used PacBio reads and Hi-C to assemble a chromosome-level reference genome for M. macrocephalus. We generated family segregation information to construct a genetic map, pool-seq of males and females to characterize its sex system, and RNA-seq to highlight candidate genes of M. macrocephalus sex determination. ResultsM. macrocephalus reference genome is 1,282,030,339 bp in length and has a contig and scaffold N50 of 5.0 Mb and 45.03 Mb, respectively. Based on patterns of recombination suppression, coverage, Fst, and sex-specific SNPs, three major regions were distinguished in the sex chromosome: W-specific (highly differentiated), Z-specific (in degeneration), and PAR. The sex chromosome gene repertoire was composed of genes from the TGF-{beta} family (amhr2, bmp7) and Wnt/{beta}-catenin pathway (wnt4, wnt7a), and some of them were differentially expressed. ConclusionsThe chromosome-level genome of piaucu exhibits high quality, establishing a valuable resource for advancing research within the group. Our discoveries offer insights into the evolutionary dynamics of Z and W sex chromosomes in fish, emphasizing ongoing degenerative processes and indicating complex interactions between Z and W sequences in specific genomic regions. Notably, amhr2 and bmp7 are potential candidate genes for sex determination in M. macrocephalus.

genomics↗

bioRxiv2021

Notch pathway is required for protection against heat-stress in spermatogonial stem cells

Environmentally favorable conditions the sustainability of spermatogenesis is brought about by a balance between two types of division, the self-renewal division for the maintenance of the stem cell pool and the differentiation division for continuous production of spermatozoa. The production of gametes under unfavorable, stressful conditions can decrease or even be interrupted, compromising fertility parameters. Thus, the survival of spermatogonial stem cells (SSCs) is crucial for the recovery of spermatogenesis after stressful situations (e.g. high temperature). Here, we show that the Notch pathway protects the spermatogonial stem cells against thermal stress, ensuring reproductive success after normal conditions are restored. First, presenilin enhancer-2 (pen-2), the catalytic subunit of {gamma}-secretase complex, was localized in SSCs of the medaka testis. The exposure of adult males to thermal stress condition induced apoptosis in all spermatogenics cells, with the exception of SSCs. Concomitantly, the Notch pathways was up-regulated, including the pen-2, its ligands (dll4, jag1-2) and its receptors (notch1a-3); pen-2 expression was restricted to the SSCs during thermal stress. The importance of this pathway was further supported by an ex vivo approach, in which the inhibition of Notch activity induced a loss of SSCs. Overall, this study demonstrates that the Notch pathways activity is necessary for the protection of SSCs under chronic thermal stress.

cell biology↗

bioRxiv2019

Generation of a white-albino phenotype from cobalt blue and yellow-albino trouts: inheritance pattern and chromatophores analysis

Albinism is the most common color variation described in fish and is characterized by a white or yellow phenotype according to the species. In rainbow trout Oncorhynchus mykiss, aside from yellow-albino phenotypes, cobalt blue variants with autosomal, recessive inheritance have also been reported. In this study, we investigated the inheritance pattern and chromatophores distribution/abundance of cobalt blue trouts obtained from a local fish farm. Based on crosses with wild-type and dominant yellow-albino lines, we could infer that cobalt blue are dominant over wild-type and co-dominant in relation to yellow-albino phenotype, resulting in a fourth phenotype: the white-albino. Analysis of chromatophores revealed that cobalt blue trouts present melanophores, as the wild-type, and a reduced number of xanthophores. As regards to the white-albino phenotype, they were not only devoid of melanophores but also presented a reduced number of xanthophores. Cobalt blue and white-albino trouts also presented a more elongated body shape and, most remarkably, a smaller pituitary gland compared to wild-type and yellow-albino, suggesting that the allele for blue color is somehow linked with this abnormal pituitary phenotype. These phenotypes represent interesting models for research on body pigmentation in salmonids and on the mechanisms behind endocrine control of color patterning.

genetics↗