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C57BL/6JCya-Top3bem1flox/Cya
Common Name:
Top3b-flox
Product ID:
S-CKO-06415
Background:
C57BL/6JCya
Product Type
Age
Genotype
Sex
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Basic Information
Strain Name
Top3b-flox
Strain ID
CKOCMP-21976-Top3b-B6J-VA
Gene Name
Top3b
Product ID
S-CKO-06415
Gene Alias
--
Background
C57BL/6JCya
NCBI ID
21976
Modification
Conditional knockout
Chromosome
16
Phenotype
MGI:1333803
Document
Click here to download >>
Application
--
More
Rare Disease Data Center >>
Note
Note: When using this mouse strain in a publication, please cite “C57BL/6JCya-Top3bem1flox/Cya mice (Catalog S-CKO-06415) were purchased from Cyagen.”
Strain Description
Ensembl Number
ENSMUST00000023465
NCBI RefSeq
NM_011624
Target Region
Exon 3~4
Size of Effective Region
~1.2 kb
Detailed Document
Click here to download >>
Overview of Gene Research
TOP3B, short for topoisomerase III beta, is a member of the topoisomerase family. It operates on both DNA and RNA substrates, playing crucial roles in regulating gene expression and genomic stability [2]. It is involved in pathways related to R-loop resolution and is essential for maintaining genome integrity. Mutations in TOP3B are linked to neurodevelopmental and cognitive disorders, highlighting its significance for human health [2].

A homozygous deletion of the TOP3B gene in a patient with bilateral renal cancer led to genome instability, an increase in DNA damage, chromosome bridging, and a significant rise in R-loop formation, suggesting TOP3B is necessary to prevent excessive R-loop accumulation [1]. In TOP3B knockout cells, elevated R-loops were observed, which could be suppressed by TOP3B transfection. R-loop-inducing agents also induced higher R-loops in these knockout cells. TOP3B physically associates with R-loops and can cleave the single-stranded DNA displaced by the R-loop RNA-DNA duplex. It interacts with the R-loop helicase DDX5 to resolve R-loops in a pathway parallel with senataxin [3].

In conclusion, TOP3B is vital for resolving R-loops and maintaining genome stability. Its loss-of-function models, such as gene knockout in cells or in patients, have revealed its role in preventing genomic damage. These findings are significant for understanding diseases like cancer and neurodevelopmental disorders where TOP3B mutations or deletions are implicated [1,3].

References:
1. Zhang, Tao, Wallis, Mathew, Petrovic, Vida, Kalitsis, Paul, Hudson, Damien F. 2019. Loss of TOP3B leads to increased R-loop formation and genome instability. In Open biology, 9, 190222. doi:10.1098/rsob.190222. https://pubmed.ncbi.nlm.nih.gov/31795919/
2. Moreira, Filipa, Arenas, Miguel, Videira, Arnaldo, Pereira, Filipe. 2021. Molecular Evolution of DNA Topoisomerase III Beta (TOP3B) in Metazoa. In Journal of molecular evolution, 89, 384-395. doi:10.1007/s00239-021-10011-7. https://pubmed.ncbi.nlm.nih.gov/33999213/
3. Saha, Sourav, Yang, Xi, Huang, Shar-Yin Naomi, Wang, Weidong, Pommier, Yves. . Resolution of R-loops by topoisomerase III-β (TOP3B) in coordination with the DEAD-box helicase DDX5. In Cell reports, 40, 111067. doi:10.1016/j.celrep.2022.111067. https://pubmed.ncbi.nlm.nih.gov/35830799/
Quality Control Standard
Sperm Test

Pre-cryopreservation: Measurement of sperm concentration, determination of sperm viability.

Post-cryopreservation: A vial of cryopreserved sperms is selected for in-vitro fertilization from each batch.

Environmental Standards:SPF
Available Region:Global
Source:Cyagen
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