Identification of a supernumerary der(18) chromosome by a rational strategy for the cytogenetic typing of small marker chromosomes with chromosome-specific DNA probes

Rapid detection of karyotype changes in interphase bone marrow cells by oligonucleotide primed in situ hybridization (PRINS)

Fluorescence in situ hybridization (FISH) using DNA probes of several hundred or thousand base pairs in length enables the visualization of chromosomal aberrations in interphase nuclei. A new method for in situ labelling of chromosomes is the oligonucleotide primed in situ labelling (PRINS) technique. So far, this has mainly been used to demonstrate subtle changes in metaphase spreads. The aim of the present study was to investigate the suitability of PRINS for detecting chromosome gains or losses in interphase nuclei. This technique was compared with FISH analysis by examining the bone marrow cells of ten patients in whom the karyotypes were known from conventional chromosome banding. Corresponding results by both PRINS and FISH were obtained for chromosomes 1, 3, 7, 8, and Y in five patients with normal chromosome patterns, as well as in five patients with clonal karyotype changes, e.g., monosomy 7, trisomy 8, or loss of the Y chromosome. Being faster and approximately ten times less expensive, PRINS can replace FISH for detecting numerical karyotype changes.

Prostate-specific membrane antigen: evidence for the existence of a second related human gene

Prostate-specific membrane antigen (PSM) is a glycoprotein recognised by the prostate-specific monoclonal antibody 7E11-C5, which was raised against the human prostatic carcinoma cell line LNCaP. A cDNA clone for PSM has been described. PSM is of clinical importance for a number of reasons. Radiolabelled antibody is being evaluated both as an imaging agent and as an immunotherapeutic in prostate cancer. Use of the PSM promoter has been advocated for gene therapy applications to drive prostate-specific gene expression. Although PSM is expressed in normal prostate as well as in primary and secondary prostatic carcinoma, different splice variants in malignant tissue afford the prospect of developing reverse transcription-polymerase chain reaction (RT-PCR)-based diagnostic screens for the presence of prostatic carcinoma cells in the circulation. We have undertaken characterisation of the gene for PSM in view of the protein's interesting characteristics. Unexpectedly, we have found that there are other sequences apparently related to PSM in the human genome and that PSM genomic clones map to two separate and distinct loci on human chromosome 11. Investigation of the function of putative PSM-related genes will be necessary to enable us to define fully the role of PSM itself in the development of prostatic carcinoma and in the clinical management of this malignancy.

Molecular cytogenetic study of supernumerary marker chromosomes in an unselected group of children

We report on an unselected group of 24 children with small supernumerary marker chromosomes, found in a large sample of 34,910 consecutive newborns karyotyped at birth. Sixteen of these were available for reexamination. With the use of in situ hybridization with alpha-satellite centromere probes and satellite III, ribosomal and beta-satellite DNA probes, we have characterized these markers. In 14 of the 16 cases we have been able to determine the chromosomal origin of the marker. Twelve of the markers are derived from the acrocentric chromosomes. Of these 12 markers, 4 are derived from chromosome 14, 4 from chromosome 22, 3 from chromosome 15 and one is from either chromosome 13 or 21. Ten of these markers were initially ascertained with the satellite III DNA probe, taking advantage of the fact that satellite III DNA is found in the centromeric region of the following chromosomes: 1, 5, 9, 13, 14, 15, 16, 20, 21, 22, and Y. Two markers were derived from chromosomes 4 and 8. The origin of the last 2 markers could not be determined with the techniques employed. Only one of these children is psychometrically retarded and has a peculiar appearance. Unfortunately we were not able to determine the origin of the marker in her case. All other children developed normally.

PRINS as a method for rapid chromosomal labeling on human spermatozoa

Direct in situ labeling of human spermatozoa was performed using the PRINS method. This technique is based on annealing of specific oligonucleotide primers, and subsequent primer extension by a Taq DNA polymerase. The reaction was carried out on a programmable temperature cycler, and labeling was obtained in a 1-hr reaction. The method was successfully tested with specific primers for chromosomes 13, 16, and 21. This suggests that PRINS may be a fast and reliable technique for detecting aneuploidies.