Localization of the single copy gene <i>Mdh2</i> on <i>Xenopus tropicalis</i> chromosomes by FISH-TSA

Abstract

A single copy gene, mitochondrial malate dehydrogenase 2 (Mdh2), was localized on Xenopus tropicalis chromosomes by fluorescence in situ hybridization coupled with tyramide signal amplification (FISH-TSA). The respective cDNA was cloned and sequenced. The labeled probe hybridized with a subcentromeric region of the long arms of homologous chromosomes 3. Results of comparison of the gene localization with previously mapped X. laevis paralogs strongly suggest a common evolutionary origin of chromosomes 3 and 8 in X. laevis and chromosome 3 in X. tropicalis. This is the first time that a single copy gene has been visualized on X. tropicalis chromosomes. The FISH-TSA method gives a strong signal with a 1-kb labeled probe.

Chromosome Banding in Amphibia. XXXII. The Genus Xenopus (Anura, Pipidae)

“…In their pioneering cytogenetic work on the genus Xenopus , Janina Tymowska and co-workers (for references, see table 1 ) did not arrange the ordinarily stained chromosomes according to decreasing lengths, but established sophisticated standard karyotypes which were based on the relative sizes of short and long chromosome arms. Subsequently, these unconventional chromosome groupings were adopted by others in studies on chromosome banding [Sekiya and Nakagawa, 1983;Schmid et al, 1987;Schmid and Steinlein, 1991], chromosome painting [Krylov et al, 2010] and mapping of genes and repetitive DNA sequences [Courtet et al, 2001;Krylov et al, 2003Krylov et al, , 2007Tlapakova et al, 2005;Nanda et al, 2008;Uno et al, 2008Uno et al, , 2013. In the present study, this system is simplified and the chromosomes are arranged according to the new nomenclature of Xenopus chromosomes established by the Xenopus Gene Nomenclature Committee [Matsuda et al, this issue].…”

Working map of the lampbrush chromosomes of Xenopus tropicalis: A new tool for cytogenetic analyses

“…Position of the centromeres on LBCs of X. tropicalis could now be determined by in situ hybridization of centromeric repeat one (Fcr1) probe as for X. laevis (Edwards and Murray, 2005) or by injecting transcripts of the myc-tagged CENP-C protein in the X. tropicalis oocyte (Joseph Gall, Carnegie Institution, personal communication). The other would be to carry out in situ hybridization of specific probes for single copy genes on both sets of chromosomes, a technique which has been applied successfully to X. tropicalis mitotic chromosomes (Krylov et al, 2007). The most striking feature of X. tropicalis GV spreads was that each of the 10 LBCs exhibited one or several specific morphological characteristics which made their identification unambiguous.…”

Wolbachia co-infection in a hybrid zone: discovery of horizontal gene transfers from two Wolbachia supergroups into an animal genome

“…Slides were denatured and hybridized in the presence of 50 µl of the hybridization mixture under a coverslip for 5 min at 70 • C. Hybridization mixture was composed of 2 µl of labeled probe, 50% formamide, 2X SSC, 300 mM NaCl, 30 mM sodium citrate, pH 7.0. After denaturing, slides were left overnight in a wet chamber at 37 • C. Posthybridization washing and visualization of FISH-TSA (tyramide signal amplification) probes were performed as described previously (Krylov, Tlapakova & Macha, 2007;Krylov et al, 2008). Detection of probes with antidigoxigenin conjugated to horseradish peroxidase (Roche) was done at a concentration of 1:2,000 in TNB (Tris-NaCl-blocking buffer).…”