TY  - JOUR
A1  - Kneitz, Susanne
A1  - Mishra, Rasmi R.
A1  - Chalopin, Domitille
A1  - Postlethwait, John
A1  - Warren, Wesley C.
A1  - Walther, Ronald B.
A1  - Schartl, Manfred
T1  - Germ cell and tumor associated piRNAs in the medaka and \(Xiphophorus\) melanoma models
JF  - BMC Genomics
N2  - Background
A growing number of studies report an abnormal expression of Piwi-interacting RNAs (piRNAs) and the piRNA processing enzyme Piwi in many cancers. Whether this finding is an epiphenomenon of the chaotic molecular biology of the fast dividing, neoplastically transformed cells or is functionally relevant to tumorigenesisis is difficult to discern at present. To better understand the role of piRNAs in cancer development small laboratory fish models can make a valuable contribution. However, little is known about piRNAs in somatic and neoplastic tissues of fish.

Results
To identify piRNA clusters that might be involved in melanoma pathogenesis, we use several transgenic lines of medaka, and platyfish/swordtail hybrids, which develop various types of melanoma. In these tumors Piwi, is expressed at different levels, depending on tumor type. To quantify piRNA levels, whole piRNA populations of testes and melanomas of different histotypes were sequenced. Because no reference piRNA cluster set for medaka or Xiphophorus was yet available we developed a software pipeline to detect piRNA clusters in our samples and clusters were selected that were enriched in one or more samples. We found several loci to be overexpressed or down-regulated in different melanoma subtypes as compared to hyperpigmented skin. Furthermore, cluster analysis revealed a clear distinction between testes, low-grade and high-grade malignant melanoma in medaka.

Conclusions
Our data imply that dysregulation of piRNA expression may be associated with development of melanoma. Our results also reinforce the importance of fish as a suitable model system to study the role of piRNAs in tumorigenesis.
KW  - small RNA-sequencing
KW  - melanoma
KW  - piRNA
KW  - fish model
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146028
VL  - 17
IS  - 357
ER  - 
TY  - JOUR
A1  - Schartl, Manfred
A1  - Kneitz, Susanne
A1  - Volkoff, Helene
A1  - Adolfi, Mateus
A1  - Schmidt, Cornelia
A1  - Fischer, Petra
A1  - Minx, Patrick
A1  - Tomlinson, Chad
A1  - Meyer, Axel
A1  - Warren, Wesley C.
T1  - The piranha genome provides molecular insight associated to its unique feeding behavior
JF  - Genome Biology and Evolution
N2  - The piranha enjoys notoriety due to its infamous predatory behavior but much is still not understood about its evolutionary origins and the underlying molecular mechanisms for its unusual feeding biology. We sequenced and assembled the red-bellied piranha (Pygocentrus nattereri) genome to aid future phenotypic and genetic investigations. The assembled draft genome is similar to other related fishes in repeat composition and gene count. Our evaluation of genes under positive selection suggests candidates for adaptations of piranhas’ feeding behavior in neural functions, behavior, and regulation of energy metabolism. In the fasted brain, we find genes differentially expressed that are involved in lipid metabolism and appetite regulation as well as genes that may control the aggression/boldness behavior of hungry piranhas. Our first analysis of the piranha genome offers new insight and resources for the study of piranha biology and for feeding motivation and starvation in other organisms.
KW  - whole-genome sequencing
KW  - genome annotation
KW  - comparative genomics
KW  - RNA-seq transcriptome
KW  - energy homeostasis
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202218
VL  - 11
IS  - 8
ER  -