Chromosome maps of man and mouse

Graphical displays and listings are presented showing the chromosomal locations of the loci referred to in the Edinburgh Human Gene Mapping Conference (1979), those regarded as homologous between mouse and man, and some others used in linkage studies of chromosomal rearrangements in the mouse. These are all stored on the files of a small computer allowing simple updating and modification.     

Chromosome maps of man and mouse II

Chromosome displays and listings are presented showing loci whose position is known in both man and mouse, in similar manner to our previous report (Dalton et al. 1981). There is now evidence for at least 27 conserved autosomal segments with two or more loci in the two species. The human and mouse chromosome maps show the location of homologous genes. The mouse map also shows the positions of translocations used in gene location and of some other genes used in linkage studies on them.     

Chromosome maps of man and mouse. IV

Current knowledge of man-mouse genetic homology is presented in the form of chromosomal displays, tables and a grid, which show locations of the 322 loci now assigned to chromosomes in both species, as well as 12 DNA segments not yet associated with gene loci. At least 50 conserved autosomal segments with two or more loci have been identified, twelve of which are over 20 cM long in the mouse, as well as five conserved segments on the X chromosome. All human and mouse chromosomes now have conserved regions; human 17 still shows the least evidence of rearrangement, with a single long conserved segment which apparently spans the centromere. The loci include 102 which are known to be associated with human hereditary disease; these are listed separately. Human parental effects which may well be the result of genomic imprinting are reviewed and the location of the factors concerned displayed in relation to mouse chromosomal regions which have been implicated in imprinting phenomena.     

Chromosome assignment of genes encoding theα andΒ subunits of glycoprotein hormones in man and mouse

The chromosomal locations of the genes for the common α subunit of the glycoprotein hormones and the Β subunit of chorionic gonadotropin in humans and mice have been determined by restriction enzyme analysis of DNA isolated from somatic cell hybrids. The CGα gene (CGA), detected as a 15-kb BamHI fragment in human DNA by hybridization to CGα cDNA, segregated with the chromosome 6 enzyme markers ME1 (malic enzyme, soluble) and SOD2 (superoxide dismutase, mitchondrial) and an intact chromosome 6 in human-rodent hybrids. Cell hybrids containing portions of chromosome 6 allowed the localization of CGA to the q12 → q21 region. The >30- and 6.5-kb BamHI CGB fragments hybridizing to human CGΒ cDNA segregated concordantly with the human chromosome 19 marker enzymes PEPD (peptidase D) and GPI (glucose phosphate isomerase) and a normal chromosome 19 in karyotyped hybrids. A KpnI-HindIII digest of cell hybrid DNAs indicated that the multiple copies of the CGΒ gene are all located on human chromosome 19. In the mouse, the α subunit gene, detected by a mouse thyrotropin (TSH) α subunit probe, and the CGΒ-like sequences (CGΒ-LHΒ), detected by the human CGΒ cDNA probe, are on chromosomes 4 and 7, respectively.     

Fibrous histiocytoma cell line: Chromosome studies of mouse and man

A human cell line isolated from a lung metastasis of a malignant fibrous histiocytoma was studied chromosomally. The cell line had a modal chromosome number of 59 with multiple numerical and morphologic chromosome changes and marker chromosomes. A putative clone from this cell line had a modal number of 41 with exclusively acrocentric chromosomes and was clearly not human but mouse in origin.     

Comparison of cAMP-specific phosphodiesterase mRNAs distribution in mouse and rat brain

There are eleven families of phosphodiesterases that regulate cellular levels of cyclic nucleotides by degradation of cAMP or cGMP. Knowledge of the expression sites of different PDE genes in brain is of special importance for studies on development of specific inhibitors considering that, for example, PDE4 inhibitor treatments exhibit profound anti-inflammatory effects. To address possible species differences we examined the expression of mRNAs coding for the cAMP specific PDE4 and PDE7 families since inhibitors have been used in clinic for schizophrenia, mood disorders, cognition and inflammatory diseases treatment. We have compared the expression of these PDEs in mouse brain by in situ hybridization histochemistry in comparison with rat brain and found that their neuroanatomical distribution differs in a few areas.     

Chromosome location of four genes in Leishmania

Chromosome-sized DNA molecules from Leishmania isolates (L. mexicana amazonensis, L. mexicana mexicana, L. chagasi, L. major, L. donovani, and L. braziliensis) were separated by orthogonal field alternation gel electrophoresis. The chromosome locations of four genes were mapped. The alpha-tubulin and rRNA genes each mapped to a single chromosome size class. The beta-tubulin and the 5'-spliced-leader-sequence genes were found on more than one chromosome size class and showed variation of hybridization profiles across species.     

Chromosome 16 tumor-suppressor genes in breast cancer

Loss of heterozygosity on the long arm of chromosome 16 is one of the most frequent genetic events in breast cancer, suggesting the presence of one or more classic tumor-suppressor genes (TSGs). It has been shown that E-cadherin is the TSG on 16q in lobular tumors. In a search for the target genes in more frequently occurring low-grade nonlobular tumors, the smallest region of overlap (SRO) in this area of the genome has been exhaustively searched for. However, the results have demonstrated remarkable complexity, and so a clear consensus on identification of the SRO boundaries has not been reached. Several genes in the vicinity of these SROs have been scrutinized as putative TSGs in breast cancer, but so far, none has fulfilled the criteria for target genes. This review discusses the complexity of the 16q region and the different approaches that have been, are being, and will be used to detect the target genes in this area.     

Chromosome aberrations and genes in human and experimental leukemias

Although determination of chromosomal abnormalities may be of limited usefulness for the diagnosis of leukemia, the recent advances in the molecular mechanism associated with chromosome aberration has been rapid. Chromosome translocation in Burkitt lymphoma and chronic myeloid leukemia was the most striking evidence for the oncogene activation. Other specific chromosome abnormalities for FAB-classified leukemias are also known. Translocated type of chromosome abnormalities between immunoglobulin or T-cell receptor genes and oncogenes may also affect the T and B-cell leukemogenesis. However, the role of trisomies found in human and experimental leukemias and the gene dosages had been thought to be most important until 1982, has not been unclear. Many types of phenotypically heterogeneous leukemias have been reported. t(4 ; 11) acute leukemia is one such leukemia which shows early B-cell and myelomonocytic nature. Heterogeneous leukemias have been called biphenotypic, hybrid and acute mixed leukemias. The terminology must be used the unified. Recent trials to use paraffin-fixed tissues and bone marrow smear for molecular analysis has been successfully reported. Basic analysis on the DNA degradation mechanism revealed the enzymatic activity might play an important role before the complete fixation.     

Identification of five lymphocyte activating determinants in man.

Eleven putative LD-1 locus homozygous cell donors were found by MLC tests in non-consanguineous families. Lymphocytes from each of them were used as stimulating typing cells in MLC tests together with responding cells from the other homozygous cell donors and from 45 random unrelated individuals. Four of the stimulating typing cells were found to identify a determinant in non-random association with HL-A7; LD-7a, three other cells typed for a determinant non-randomly associated with HL-A8; LD-8a, and one cell seems to identify LD-W5 in non-random association with W5. Two possible additional LD-1 determinants, LD-oh and LD-om, were less well defined with two of the cells. The combined gene frequency of the five possible LD-1 determinants is approximately 0.45 among Norwegians.     

Sex-linked genes in man and the Lyon hypothesis

Out of a total of 60 sex-linked or probably sex-linked genes in man, 34 have no known effects in the heterozygous condition, and in another 4 the known effects are of a humoral kind and hence cannot give any information concerning the Lyon hypothesis (l.h.). Of the remainder, 17 genes have known or suspected effects in heterozygous women which are multicellular in nature; though these could, in principle, give rise to the patchwork mosaic manifestation demanded by the l.h., there is not a single really plausible case amongst them and none which can be so interpreted without various ad hoc assumptions. The claim that the heterozygous phenotype of several of these conditions supports the l.h. can thus be shown to be without foundation. In the remaining five conditions, effects on the cellular level have been identified. In one of them (Xg), there is no evidence for the existence of two red cell populations in heterozygous women. Evidence for the existence of two distinct cell populations comes mainly from G-6-PD deficiency and, in a less complete form, from agammaglobulinaemia and Hurler's syndrome. In the first of these, the ‘ mosaic’ is so fine grained as to be difficult to reconcile with the l.h., which postulates inactivation early in embryonic life. Moreover, there is evidence that this phenomenon is not confined to sex-linked genes, but occurs similarly in autosomal conditions. It is concluded that the behaviour of sex-linked genes in man (like that in other mammals) gives no support to the Lyon hypothesis.     

Peripheral development of B cells in mouse and man

Summary:  In man and in mouse, B-cell maturation occurs in steps, first in the bone marrow from hematopoietic precursors to immature/transitional B cells, then in the periphery from transitional to fully mature B cells. Each developmental step is tightly controlled by the expression and function of the B-cell receptor (BCR) and by the ability to interact with the microenvironment. Mature B cells collaborate with T cells in the adaptive immune response, leading to the production of high-affinity antibodies. This response is very accurate, but slow. Immediately after pathogen entry, however, antibodies already present in the serum reinforce the innate immune response and contribute to the first-line defense against infection. Low-affinity natural antibodies are produced by B-1a B cells in the mouse and immunoglobulin M (IgM) memory cells in man. These antibodies represent an immediate protection against all microorganisms and the only one against encapsulated bacteria. B-1a and IgM memory B cells may function as a link between the innate and adaptive immune response and thus perform a primordial B-cell function.     

Chromosome number and development of artificial mouse oocytes and zygotes

BACKGROUND: Infertility due to the absence of gametes is one of the last frontiers in reproductive medicine. Sperm or oocyte donation is currently the only treatment option but this approach lacks the genetic contribution of both partners. Artificial production of gametes through haploidization may offer an alternative strategy. The aim of this study was to evaluate the efficiency of producing artificial oocytes and zygotes with correct chromosome number. METHODS AND RESULTS: Somatic cumulus cell nuclei were injected into non-enucleated oocytes to produce artificial zygotes and into enucleated mature mouse oocytes to produce artificial oocytes. The expected chromosome number of artificial zygotes and oocytes is 40 and 20 chromosomes respectively. Fertilization and developmental potential of artificial zygotes and oocytes inseminated by IVF or ICSI were investigated. The expected chromosome numbers were found in 12% of artificial zygotes and 15% of artificial oocytes. Varying the time interval between injection of the somatic nucleus and activation (3, 5, 8 h) tended to increase the efficiency up to 18 and 23% for zygotes and oocytes respectively. Two-cell formation rates were 90% for artificial zygotes and 37% for artificial oocytes after IVF and 53% for artificial oocytes after ICSI. Blastocyst formation rates were 15, 8 and 9% respectively. CONCLUSIONS: Chromosome number analysis shows that the efficiency of obtaining artificial zygotes and oocytes with correct chromosome number was low and that developmental potential was severely hampered. These observations question the possibility of obtaining chromosomally normal embryos from artificial oocytes or zygotes.     

Expression of genes coding for the proteins of intermediate filaments in man

Cellular morphogenesis is a fundamental phenomenon in our understanding of eucaryotic cells. When, where and how these supra molecular structures generate during differentiation to cellular shape? It seems that the cytoskeleton alone is responsible for the formation and maintenance of the cellular shape. The supra molecular organisation of the intermediate filaments is specific for the cell type, the developmental stage and the type of differentiation. The human genes coding for the different subunits of these polymers have now all been isolated, cloned and characterised. The regulation of their expression is now being analysed.