Abstract
Previously, we found that the genotype of 42 out of 198 mouse microsatellite loci, which are distributed among all chromosomes except the Y chromosome, changed from monomorphism to polymorphism (CMP) in a genetically modified inbred mouse strain. In this study, we further examined whether CMP also relates to the homologous recombination in gene knockout (KO) mouse strains. The same 42 microsatellite loci were analyzed by polymerase chain reaction (PCR) in 29 KO inbred mouse strains via short tandem sequence repeat (STR) scanning and direct sequence cloning to justify microsatellite polymorphisms. The C57BL/6J and 129 mouse strains, from which these 29 KO mice were derived, were chosen as the background controls. The results indicated that 10 out of 42 (23.8%) loci showed CMP in some of these mouse strains. Except for the trinucleotide repeat locus of D3Mit22, which had microsatellite CMP in strain number 9, the core sequences of the remaining 41 loci were dinucleotide repeats, and 9 out of 41 (21.95%) showed CMPs among detected mouse strains. However, 11 out of 29 (37.9%) KO mice strains were recognized as having CMPs. The popular dinucleotide motifs in CMP were (TG)n (50%, 2/4), followed by (GT)n (27.27%, 3/11) and (CA)n (23.08%, 3/13). The microsatellite CMP in (CT)n and (AG)n repeats were 20% (1/5). According to cloning sequencing results, 6 KO mouse strains showed insertions of nucleotides whereas 1 showed a deletion. Furthermore, 2 loci (D13Mit3 and D14Mit102) revealed CMP in 2 strains, and mouse strain number 9 showed CMPs in two loci (D3Mit22 and D13Mit3) simultaneously. Collectively, these results indicated that microsatellite polymorphisms were present in the examined inbred KO mice.
Highlights
Microsatellites, or short tandem sequence repeats (STRs), are highly polymorphic repetitive DNA sequences 1–6 base pairs in length [1] that are randomly distributed throughout eukaryotic genomes [2]
Microsatellite polymorphism analysis by STR scanning After scanning the polymerase chain reaction (PCR) products of 42 loci, several changed from monomorphism to polymorphism (CMP) were detected in parts of the genomes of the mouse strains at different loci
We investigated the frequency of microsatellite CMP in 29 KO mice using 42 STR markers
Summary
Microsatellites, or short tandem sequence repeats (STRs), are highly polymorphic repetitive DNA sequences 1–6 base pairs (bp) in length [1] that are randomly distributed throughout eukaryotic genomes [2]. Due to their abundance within a genome, random occurrence, and high degree of polymorphisms [3], STRs are ideal tools for deciphering genetic variability. Microsatellites are useful for detecting genomic DNA damage and/or mutational events, e.g., deletions, insertions, and point mutations [6], based on the polymorphisms that they contain This alteration, demonstrated by the insertion or deletion of repeat units, was first observed in colorectal tumors [7,8,9,10,11]. According to the nature of the repetitive DNA sequences within them, microsatellites are prone to slippage during DNA replication, leading to variations in their size defined as microsatellite instability (MSI)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
