The SWI/SNF-family chromatin remodeling protein ATRX is a tumor suppressor in sarcomas, gliomas and other malignancies. Its loss of function facilitates the alternative lengthening of telomeres (ALT) pathway in tumor cells, while it also affects Polycomb repressive complex 2 (PRC2) silencing of its target genes. To further define the role of inactivating
ATRX
mutations in carcinogenesis, we knocked out
atrx
in our previously reported
p53/nf1
-deficient zebrafish line that develops malignant peripheral nerve sheath tumors and gliomas. Complete inactivation of
atrx
using CRISPR/Cas9 was lethal in developing fish and resulted in an alpha-thalassemia-like phenotype including reduced alpha-globin expression. In
p53/nf1
-deficient zebrafish neither peripheral nerve sheath tumors nor gliomas showed accelerated onset in
atrx
+/- fish, but these fish developed various tumors that were not observed in their
atrx
+/+ siblings, including epithelioid sarcoma, angiosarcoma, undifferentiated pleomorphic sarcoma and rare types of carcinoma. These cancer types are included in the AACR Genie database of human tumors associated with mutant
ATRX
, indicating that our zebrafish model reliably mimics a role for
ATRX
-loss in the early pathogenesis of these human cancer types. RNA-seq of
p53/nf1-
and
p53/nf1/atrx-
deficient tumors revealed that down-regulation of telomerase accompanied ALT-mediated lengthening of the telomeres in
atrx
-mutant samples. Moreover, inactivating mutations in
atrx
disturbed PRC2-target gene silencing, indicating a connection between ATRX loss and PRC2 dysfunction in cancer development.
A high-density linkage map of goldfish (Carassius auratus) was constructed using RNA-sequencing. This map consists of 50 linkage groups with 8,521 SNP markers and an average resolution of 0.62 cM. Approximately 84% of markers are in protein-coding genes orthologous to zebrafish proteins. We performed comparative genome analysis between zebrafish and medaka, common carp, grass carp, and goldfish to study the genome evolution events in the Cyprinidae family. The comparison revealed large synteny blocks among Cyprinidae fish and we hypothesized that the Cyprinidae ancestor undergone many inter-chromosome rearrangements after speciation from teleost ancestor. The study also showed that goldfish genome had one more round of whole genome duplication (WGD) than zebrafish. Our results illustrated that most goldfish markers were orthologous to genes in common carp, which had four rounds of WGD. Growth-related regions and genes were identified by QTL analysis and association study. Function annotations of the associated genes suggested that they might regulate development and growth in goldfish. This first genetic map enables us to study the goldfish genome evolution and provides an important resource for selective breeding of goldfish.
Hucho taimen (Pallas) is an endangered species in China. To evaluate the species' genetic diversity and population genetic structure, we isolated six polymorphic microsatellite markers from its genomic libraries by (ACA) 16 enriched, and characterized using 61 wild individuals. The number of alleles per locus ranged from two to seven, expected heterozygosity ranged from 0.3200 to 0.7410, polymorphism information content ranged from 0.3047 to 0.6896. These markers will be useful for the genetic variation assessment of taimen .
Intermuscular bones (IBs) are small, hard-boned spicules located in the muscle tissue that mainly exist in the myosepta of lower teleosts, which hurt the edibleness and economic value of fish. The study of the development of IBs is very important for freshwater aquaculture fish, but the molecular mechanism of its formation and the key regulatory genes remain unclear. In this study, we first constructed two types of zebrafish mutants (the mutants losing IBs and the mutants with partial deletion of IBs) by knocking out bmp6. We then carried out a transcriptomic analysis to reveal the role of bmp6 in the developmental mechanism of IBs; we used the caudal musculoskeletal tissues of these mutants and wild-type zebrafish at three development stages (20, 45, and 60 dph) to perform transcriptomic analysis. The results showed that the deficiency of bmp6 upregulated sik1 and activated the TNF-A signaling via the NF-KB pathway, which inhibited the development of osteoblasts and promoted osteoclast formation, thereby inhibiting the formation of IBs. These results provided insights to understand the role of bmp6 in the development of IBs in zebrafish and are useful for selective breeding of IBs in cyprinids.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.