Linda A. Cannizzaro

Regional chromosome localization of human papillomavirus intergration sites near fragile sites, oncogenes, and cancer chromosome breakpoints

The integration sites of human papillomavirus (HPV) DNA within the cervical carcinoma cell line C4-I and a primary cervical tumor were mapped by in situ hybridization. Cloned cellular sequences flanking the integrated viral DNA were used as probes. For the cell line, the viral integration site was mapped to chromosome region 8q21-q22.3, while in the primary tumor chromosome band 3p21 was the target for integration. The HPV DNA integration appears to occur in the vicinity of fragile sites, oncogenes, and chromosome breakpoints that are characteristic of hematologic malignancies and solid tumors. The integration of HPV may thus promote chromosome changes in cancer cells.

Chromosome localization of human ARH genes, a ras-related gene family

The human ARH genes (previously called RHO) share several properties with the ras gene family. Three members of the ARH family, the H6, H9, and H12 genes, have been localized to human chromosomes 2, 5, and 3, respectively. Analysis of DNAs from a rodent-human somatic cell hybrid panel demonstrates linkage of H6 to chromosome region 2p12----2pter and H9 to region 5q33----5qter. In situ chromosome hybridization also showed that the primary site for H9 is in the 5q31----qter region. The H12 gene was some-what difficult to localize using rodent-human hybrids because the probe detects a family of rodent genes as homologous to the human probe as in the human cognate gene. However, chromosome in situ hybridization revealed grains clustered in region 3p14----3p22 with a significant peak in band 3p21. We conclude that H6 is in 2p12----pter, H9 in 5q31----5qter, and H12 in 3p21.

Chromosomes 17 and 22 involved in marker formation in neurofibrosarcoma in von Recklinghausen disease

SummaryWe describe the cytogenetic findings in a recurrent neurofibrosarcoma in a patient with nonfamilial von Recklinghausen disease. The composite karyotype was: 40,Y,-X,+dic r(X;20)(:Xp22.2→q26::20p13→ q13:), -1, +der(1)t(1;3) (p21;p24),-3,-4,-5,+der(5) t(5;?)(q31;?),-9,-9,+der(9)t(3;9)(q21 or q13;p24 or p22), -11,+der(11)t(11;?)(q22.2;?), -17,+der(17)t(17; 22;?)(q21;q13.1;?), -20, -21, -22, -22, +der(22)t(17; 22;?)(q21;q13.1;?),t(2;10)(q37;q22). The derivative chromosomes were demonstrated at the 500 band level. Chromosomes 17 and 22 were shown to be involved in an unbalanced three-way translocation: t(17;22;?)(q21;q13.1;?). This event was confirmed by in situ hybridization, using two probes mapped to chromosome 17. Hill H is a probe derived from the novel oncogene TRE and is located at 17q12–22. The second probe, derived from the granulocyte colony-stimulating factor (G-CSF), is located at 17q11–q21. The rearrangement between chromosomes 17 and 22 showed breakpoints similar or close to the gene loci for neurofibromatosis 1 (NF-1) and NF-2. Based on our observations we recommend that genetic studies on NF-1 tumors include both gene sites (NF-1 and NF-2) rather than focus on one gene locus.

Chromosome sublocalization of a cDNA for human DNA polymerase-β to 8p11→p12

We have localized a cDNA fragment that codes for human DNA polymerase-β. Using somatic cell and in situ hybridization techniques, this cDNA was cloned by screening a human KM-3 cell cDNA library in λg

The breakpoint in 22q11 in a case of Ph-positive acute lymphocytic leukemia interrupts the immunoglobulin light chain gene cluster

With a constant region probe (c-lambda) from the immunoglobulin light chain gene cluster, we performed in situ hybridization to bone marrow chromosome preparations from a patient with a Ph-positive form of acute lymphocytic leukemia. Results in this patient indicate that the immunoglobulin chain genes were involved in the 9;22 chromosome rearrangement.

Chromosomal localization of human genes required for G1 progression in mammalian cells

Specific probes derived from the human genes that complement the mutations of two independent temperature-sensitive (ts) mutants of the BHK-21 hamster cell line were used to determine the chromosomal locations of the loci in the human genome. The ts11 gene, which complements a mutation that blocks progression through the G1 phase of the cell cycle and which has now been identified as the structural gene for asparagine synthetase, is a member of a small gene/pseudogene family with four members. In a rodent-human somatic cell hybrid panel, the ts11 genomic locus from which the genomic probe derives segregates with human chromosome region 7cen----7q35, proximal to the TCR beta locus. In situ hybridization maps this locus more precisely to the q21-31 region of chromosome 7. Two other members of the gene family detected by the ts11 probe segregate concordantly with chromosome region 8pter----8q24 and chromosome region 21pter----21q22. Similar experiments using the same rodent-human hybrid panel conducted with a probe identifying the tsBN51 gene, which also encodes a function necessary for G1 progression, mapped this locus to human chromosome 8, proximal to the large amplification unit encompassing the c-myc gene of Colo320 cells. Chromosomal in situ hybridization of the tsBN51 probe confirmed the localization of this gene to chromosome 8, with the most likely location of the gene being 8q21.

805 IN SITU HYBRIDIZATION AND TRANSLOCATION BREAKPOINT (DGS) MAPPING III. DiGEORGE SYNDROME (DGS) WITH PARTIAL MONOSOMY OF CHROMOSOME 22

DiGeorge Syndrome is characterized by a spectrum of congenital malformations. Studies have shown an association between DGS and deletion of chromosome 22 resulting in the loss of 22 pter→q11 and translocation of its distal long arm (22q11→qter) to one of several autosomes (3q, 4q, 10q, 20q). Two cell lines were used for this study. The first, from a balanced translocation carrier, the father of a patient with DGS, has a karyotype of 46, XY, t(10;22)(q25, q11). The der 22 extending from 22pter to q11 is retained. The second cell line, established from a DGS patient, has a karyotype of 45, XY, -4, -22, + der (4), t(4;22)(q35.2;q11.2). This line is monosomic for the region 22pter to q11 and for the region 4q35.2 to qter. “In situ” hybridization with a constant region probe for the immunoglobulin light chain gene cluster (IGLC) reveals strong hybridization to the normal 22 in the q11 region and to the other involved translocation chromosome, 10q+ or 4q+. No hybridization was observed to the der 22 of the balanced carrier. These esults suggest that all of the IGLC constant region from chromosome 22 is translocated to the relevant autosomes involved in these DGS related rearrangements and the breakpoint for each rearrangement is proximal to the c-lambda locus in 22q11. It is possible that the breakpoint for DGS lies within the variable region since v-lambda is proximal to c-lambda in 22q11.