摘要:

Chromosomal pairing and chiasma formation were studied two individuals of Peromyscus beatae heterozygous for the presence of a large block of interstitial heterochromatin. Although the modified chromosome was of medium size, analysis of C-banded diakinetic configurations revealed that it was the homolog of one of the smallest autosomes. Analysis of silver stained synaptonemal complexes indicated that synapsis was either unidirectional from initiation at one set of telomeres or was bidirectional from initiation at both sets of telomeres. Each pattern resulted in characteristic heteromorphic pairing configurations (interstitial asynapsis or terminally positioned unpaired segments) in early pachynema. These configurations underwent synaptic adjustment and, by mid-pachynema, the lateral elements of the polymorphic bivalent either appeared typical of homomorphic bivalents or exhibited regional heteropycnosis in one or both axes. Synaptonemal complex data for Peromyscus and many other mammalian species reflect an apparent need for fully paired, linear bivalents prior to the end of pachynema.

ISSN:1424-8581    

DOI:10.1159/000132709

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Synaptonemal complex (SC) autoantibodies are spontaneously produced by patients with various autoimmune diseases. Immunofluorescence staining of pachytene cells localized the antigen to the central element or transverse filaments of the SC but not to the lateral elements. Specific antibody labeling was confined to the SC at synapsis. Cytochemical tests showed that the SC autoantigen is a basic protein possibly bound to DNA. An unusual characteristic of the SC autoantigen is its species specificity. Patients were found whose sera selectively labeled the SCs of other humans, mice, or newts. The combining of anti SC and anti-kinetochore antibodies provides a new immunocytochemical method for the analysis of SC karyotypes. The optimum conditions for preparation of pachytene cells for visualization by indirect immunofluorescence were determined. The nature and functions of the SC antigen, as well as possible applications of SC-specific autoantibodies in cytogenetics and cell biology, are discussed.

ISSN:1424-8581    

DOI:10.1159/000132710

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Mice heterozygous for one or more Robertsonian (Rb) translocation chromosomes have been used to analyze synaptonemal complex (SC) configurations and kinetochore arrangements in trivalents and multivalents. Rb heterozygosity without arm homologies leads to the formation of heteromorphic trivalents in meiosis I; alternating homology of the chromosome arms produces ringlike or chainlike multivalents. Immunofluorescence double-labeling with human antibodies to SCs and kinetochores was performed on surface-spread pachytene spermatocytes. Both Rb bivalents and Rb trivalents clearly showed that metacentrics possess only one centromere. In heteromorphic trivalent SCs, the nonhomologous kinetochores of the two acrocentrics were closely paired in a cis configuration and juxtaposed opposite the kinetochore of the metacentric; the latter appeared to be an integral part of the longitudinal SC axis. Meiotic multivalents of interpopulation hybrids included up to 36 chromosome arms. In multivalent SCs, the kinetochores always lay together, with the SC arms arranged away from the central centromere cluster. The paracentromeric regions of the Rb chromosomes appeared to remain unsynapsed on both sides of the centromeres. The SC arms were often linked by end-to-end associations. Following desynapsis of the multivalent SC, the kinetochores of the Rb metacentrics showed a highly nonrandom topologic distribution within the nucleus, reminiscent of their arrangement during synapsis.

ISSN:1424-8581    

DOI:10.1159/000132711

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

From the analysis of mouse × rat cell hybrids which segregate rat chromosomes, the rat genes coding for the enzymes medium-chain acyl-CoA dehydrogenase, isovaleryl-CoA dehydrogenase, and the β-subunit of propionyl-CoA carboxylase have been assigned to chromosomes 2, 3, and 8, respectivel

ISSN:1424-8581    

DOI:10.1159/000132712

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The aromatic diamidine berenil specifically inhibits the condensation of a subset of constitutive heterochromatin in human lymphocyte cultures. In the normal male chromosome complement, only the quinacrine-brilliant Y heterochromatin exhibits distinct undercondensation. The optimal culture conditions for inhibiting heterochromatin condensation are achieved when berenil is added at a final concentration of 150 µg/ml 24 h before cell harvest. Various examples of the use of berenil in the analysis of chromosome rearrangements involving quinacrine-brilliant heterochromatin are presented. A variant, giant-satellited chromosome 22 was found to respond to berenil treatment, although its enlarged and quinacrine-bright short-arm region did not contain Y heterochromatin. Southern blot analysis and chromosome in situ hybridization suggested that most chromosome 22 variants do not stem from Y; acrocentric translocations. The experimentally undercondensed Y heterochromatin is characterized by moderate C-band labeling, bright quinacrine fluorescence, and specific silver staining. At the ultrastructural level, undercondensation is associated with loosely packed, mutliply folded chromatin fibers with a diameter of approximately 250 Å and organized probably as loop

ISSN:1424-8581    

DOI:10.1159/000132713

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Analyses of Southern blots of rodent × owl monkey somatic cell hybrids permitted syntenic assignment of gene loci coding for triosephosphate isomerase (TPI), antigen CD4(T4), Kirsten rat sarcoma 2 (KRAS2) virus, insulin-like growth factor 1 (IGF1), and α2-macroglobulin (A2M) to chromosome 10 of owl monkey karyotype VI (2n = 49, 50). In addition, regional in situ localization of the T4 and KRAS2 loci on the proximal region of the long arm of this acrocentric chromosome and on the corresponding homologous region on the long arm of metacentric chromosome 1 of karyotype IV (2n = 52) substantiated our hypothesis that a single fusion or fission event is responsible for the polymorphism in chromosome number characteristic of owl monkeys from at least three allopatric populations. The study supports a putative homoeology between owl monkey chromosome 10 (K-VI) and human chromosome 12. The morphological differences between these two primate chromosomes indicate evolutionary rearrangements involving at least one pericentric inversio

ISSN:1424-8581    

DOI:10.1159/000132714

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The gene encoding the E1α subunit of branched chain α-ketoacid dehydrogenase was mapped to human chromosome . 19.32P-labeled human Elα cDNA was hybridized with DNA derived from flow-sorted human chromosomes; it hybridized exclusively with that from chromosome

ISSN:1424-8581    

DOI:10.1159/000132715

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Using a cDNA probe of the rat angiotensinogen gene (ANG), restriction fragment length polymorphisms (RFLPs) were detected in inbred rat strains with the restriction enzymes Hindlll, PstI, and Pvull. Three alleles of ANG were almost equally distributed in 11 inbred strains. In two sets of backcross progeny originating from parental strains with different alleles, no close linkage was found between the ANG locus and 17 other loci tested. In situ hybridization, however, allowed assignment of the gene to chromosome 19q. The RFLPs of the angiotensinogen gene, therefore, can be considered useful as markers of rat chromosome 19.

ISSN:1424-8581    

DOI:10.1159/000132716

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Proteins HC and HI-30 of inter-alpha-trypsin inhibitor light chain are two plasma proteins. They are encoded by the same monocistronic mRNA. Their function is probably related to the regulation of immunologic and/or inflammatory responses. Using a genomic DNA probe and a panel of somatic cell hybrids we have mapped the gene coding for the proteins to chromosome 9. In situ hybridization experiments refined the assignment to the region 9q22.3→q3

ISSN:1424-8581    

DOI:10.1159/000132717

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

A whole-arm translocation involving the short arm of chromosome 7 and the long arm of chromosome 1 occurs nonrandomly in myelodysplastic syndrome and acute nonlymphocytic leukemia. In situ hybridization, using α satellite DNA specific for the centromeric regions of chromosomes 1 (probe pSD1-1) and 7 (probe p21-4), was performed to determine the exact breakpoints of the translocation. Both probes hybridized to the centromeric region of the translocation chromosome in metaphases from two patients with myelodysplastic syndrome. Both probes hybridized with approximately equal strength to either chromosome 1 or 7 and to the 1;7 translocation chromosome, suggesting that the t(1;7) had retained the chromosome-specific α satellite DNA from both chromosomes. These studies permit us to propose a new description, t(1;7)(cen;cen), for this translocatio

ISSN:1424-8581    

DOI:10.1159/000132718

出版商:S. Karger AG    

年代:1989

数据来源: Karger