Bodil Lomholt

Fine mapping of human 5S rRNA genes to chromosome 1q42.11→q42.13

The human 5S rRNA genes have been localized by in situ hybridization to metaphase chromosomes. Tritiated RNA probes were made by transcription from 2.300-bp and 638-bp DNA fragments containing an isolated human 5S rRNA gene. Hybridization to metaphase spreads from a balanced reciprocal translocation carrier, 46,XX.t(1:7)(q42.13;p11.1), showed that the 5S rRNA genes were entirely localized on the normal and the derivative chromosome 1. This narrows the chromosome position of the major fraction of 5S rRNA genes and pseudogenes to the region 1q42.11----q42.13.

Additional assignment of the human 5S rRNA genes to chromosome region 1q31

A major fraction of the human 5S rRNA genes has previously been assigned to chromosome region 1q42.11-->q42.13 (Sørensen et al., 1991). Through in situ hybridization of different tritiated probes to metaphase spreads, we have demonstrated that a minor fraction of the 5S rRNA genes is localized at band 1q31. This fraction amounts to 25-30% of the genes found in the region 1q42.11-->q42.13. Results obtained with the chromosomes of a balanced translocation carrier involving this region indicate that the major cluster is localized in band 1q42.13.

Porcine 5S rRNA genes map to 14q23 revealing syntenic relation to human HSPA6- and 7

5S rRNA is one of the two small RNA molecules localized in the large ribosomal subunit and thereby is involved in protein synthesis. 5S rRNAs from many different organisms have been sequenced, and more than 700 5S rRNA transcripts and 5S rRNA gene sequences have been compiled (Specht et al. 1991). The 5S rRNA genes have been studied in a large number of organisms (reviewed in Korn 1982; Geiduscheck and Tocchini-Valentini 1988; Willis 1993). Compared with the lower eukaryotes, thorough knowledge of the 5S rRNA genes in mammals is scarce. The

Detection of a few picograms of DNA on polyacrylamide gels by silver staining

DNA fragments separated on polyacrylamide gels are silver stained in ethanolamine solution. The staining procedure can be completed in 3 1/2 h. Illumination of the gels on a black background increases the sensitivity of detection compared with the usual transillumination. The limit level of detection is 3-5 pg per band with a cross-sectional area of 5 mm2. Five to fifty picograms of DNA may be detected quantitatively by scanning the gels. The method will detect 0.1 to 1 ng per band of low-molecular-weight RNA components.

Syrian hamster 5S rRNA genes are assigned to 6q2 with PNA-FISH by an R-banded karyotype

A karyotype for the Syrian hamster is proposed based on an R-banding pattern. R-bands were obtained by BrdU incorporation into the cells followed by a combined DAPI and propidium iodide staining of the fixed metaphase spreads. In situ hybridisation was performed with two biotinylated 18-mer PNA (peptide nucleic acid) probes complementary to sequences within the 5S rRNA gene. The 5S rRNA gene repeats map to chromosome 6q2. The present PNA-FISH procedure is an abbreviated and simpler version of that previously published.

Phosphohydrolases: Inorganic phosphate reaction giving stably stained zymograms using an alternative to benzidine

Abstract This paper describes a simple and stable staining reaction of inorganic phosphate applied to starch gels. During the reaction two blue redox compounds are formed, the reduction product of phosphoammonium-molybdate and the oxidation product of tetrabase. Tetrabase is a noncarcinogenic compound alternative to benzidine. Zymograms obtained by the present Pi procedure compared favorably with those obtained by reaction of the alcoholic part of an organic phosphate ester when AcP1 served as a test system. The results suggest that, when appropriate electrophoretic conditions have been worked out, the procedure may be extended to other enzymes, and possibly, to phosphohydrolases in general.

Amylase heterogeneity in Palaemonetes varians (leach) (Crustacea, Decapoda)

Abstract Amylase heterogeneity is reported in the brackish water shrimp, Palaemonetes varians. Results from population studies suggest a genetic basis involving four co-dominant alleles. In three populations from the Oresund only two alleles were found. In a fourth population from the inner part of the Roskilde Fjord two additional alleles were detected.

PNA as Specific Probe for In Situ Hybridization to Metaphase Chromosomes

The present protocol concerns a sensitive detection of biotinylated PNA probes on metaphase chromosomes by FISH (fluorescent in situ hybridization). The mono-and dibiotinylated PNA probes used are different 18-mers complementary to sequences within the 5S rRNA gene.