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Updated: Aug 23, 2026

Real-Time Quantification of the Effects of IS200/IS605 Family-Associated TnpB on Transposon Activity
Published on: January 20, 2023
Repetitive elements in the major histocompatibility complex (MHC) class I region of a teleost, medaka: identification
Megumi Y Matsuo1, Masaru Nonaka
1Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Abstract:
The repetitive elements of medaka (Oryzias latipes) are poorly characterized in spite of recent rapid progress in the medaka genome analysis. Here we report the characterization of the repetitive elements in the major histocompatibility complex (MHC) class I region, which spans about 400 kb and is one of the best characterized regions of the medaka genome. Microsatellite, low complexity regions, transposable elements, and other repeats occupied 0.68, 0.98, 7.0 and 2.9%, respectively, of the MHC class I region. Eleven transposable elements, three LTR-type, six LINE-type and two DNA-type, including several novel ones, were identified. Genomic Southern hybridization analysis indicated that these LINE-type and DNA-type elements have many copies in the medaka genome, whereas the LTR-type elements have only several copies. The comparison of the medaka MHC class I region with those of zebrafish and fugu shows the presence of three medaka lineage-specific tandem duplications of the PSMB (proteasome beta-type subunit) 8 and class Ia genes. Since eight of the 11 transposable elements were located in this region, these elements may have played a role in the medaka-specific DNA rearrangement.
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