Biomedical subjects

S Nasipuri

Publications and source records attributed to S Nasipuri.

4 recordsLinked to original sources

PubMed1991

Gene mapping by microdissection and enzymatic amplification: heterogeneity in leukaemia associated breakpoints on chromosome 11.

A new strategy for mapping chromosome translocation breakpoints in relation to known genes has been developed. This approach is based on the amplification by the polymerase chain reaction (PCR) of specific target sequences from small numbers of microdissected chromosome fragments. This method has been applied to leukaemia-associated translocations affecting the q23 region of chromosome 11. In two independent leukaemias, the t(6;11) translocation was distinguished from the t(9;11) and t(4;11) translocations by demonstrating that the former breakpoint on chromosome 11 lay proximal to the CD3D gene while the latter breakpoints lay distal to CD3D. All three translocation breakpoints were found to lie proximal to ETSI and THYI. The data suggest that although these leukaemia-associated breakpoints on chromosome 11 are cytogenetically identical they may involve disruption of different genes. This approach offers a rapid alternative to mapping by hybridisation of probes either in situ to chromosomes or to somatic cell hybrids containing the appropriate derivative chromosomes.

Base Sequence↗

PubMed1990

Rapid isolation of human chromosome-specific DNA probes from a somatic cell hybrid.

A strategy for the rapid isolation from rodent hybrids of human chromosome-specific probes by enzymatic amplification is described. Synthetic oligonucleotide primers based on the consensus Alu sequence were used to amplify inter-Alu sequence from total human genomic DNA and from a somatic cell hybrid, PNTS-1, containing one homolog of chromosome 5 as its only human complement. Direct sequence analysis of the products from human genomic DNA confirmed their inter-Alu structure and provided a novel means for the examination of the 5' end of the Alu consensus. The amplified sequences from the somatic cell hybrid DNA were cloned into a plasmid vector by blunt-end ligation, yielding clones with inserts in the range 300 to 1000 bp. More than 80% of these clones carried inserts that behaved essentially as single-copy human sequences. Hybridization of a selection of these clones to human DNA, hamster DNA, and the original hybrid DNA confirmed that they were derived from chromosome 5. Direct sequence analysis of the vector/insert boundaries in two clones confirmed that inter-Alu sequences had been cloned. This approach has significant advantages over other methods of isolating chromosome-specific probes from hybrid cells, enabling direct separation and cloning of human DNA probes that can be readily used for mapping studies.

Animals↗

PubMed1989

Gene mapping by enzymatic amplification from flow-sorted chromosomes.

A new approach to gene mapping which combines enzymatic amplification with high-resolution flow sorting of human chromosomes has been devised. Reliable amplification from as few as 200 chromosomes has been demonstrated. This method, with particular application to mapping the position of chromosomal translocations, has been used to show that the breakpoint for the constitutional translocation t(11;22)(q23;q11) lies proximal to the genes c-ets-1, Thy-1, and T3 delta and distal to the int-2 gene. The mapping was confirmed by Southern analysis to much larger numbers of chromosomes sorted from the same cell line. Control reactions for the bcl-2 gene on chromosome 18 and the C alpha gene of the IGH locus on chromosome 14 demonstrated the discrimination which can be achieved.

Base Sequence↗

PubMed1988

Differentiation and maturation of embryonal carcinoma-derived neurons in cell culture.

We have previously shown that retinoic acid-treated cultures of the P19 line of embryonal carcinoma cells differentiate into neurons, glia, and fibroblast-like cells (Jones-Villeneuve et al., 1982). We report here that the monoclonal antibody HNK-1 reacts with the neurons at a very early stage of their differentiation and is, therefore, an early marker of the neuronal lineage. Cells in differentiated P 19 cultures synthesized acetylcholine but not catecholamines, suggesting that at least some of the neurons are cholinergic. The neurons also carry high-affinity uptake sites for GABA but not for serotonin. In long-term cultures, neuronal processes differentiated into axons and dendrites, which formed synapses. This biological system should prove valuable for examining the development and maturation of cholinergic neurons, since their differentiation occurs in cell culture.

Acetylcholine↗