Rabbit Chromosomes Research Articles

Assignment1 of the parathyroid hormone/parathyroid hormone-related peptide receptor (PTHR1) to rabbit chromosome band 9p14→p13 by fluorescence in situ hybridization

Assignment<footref rid="foot01">1</footref> of the parathyroid hormone/parathyroid hormone-related peptide receptor (PTHR1) to rabbit chromosome band 9p14→p13 by fluorescence in situ hybridization

Assignment1 of the rabbit whey acidic protein gene (WAP) to rabbit chromosome 10 by in situ hybridization and description of a large region surrounding this gene

Assignment<footref rid="foot01">1</footref> of the rabbit whey acidic protein gene (WAP) to rabbit chromosome 10 by in situ hybridization and description of a large region surrounding this gene

Complete homology maps of the rabbit (Oryctolagus cuniculus) and human by reciprocal chromosome painting

Fluorescence in situ hybridization (FISH) was used to construct a homology map to analyse the extent of evolutionary conservation of chromosome segments between human and rabbit (Oryctolagus cuniculus, 2n = 44). Chromosome-specific probes were established by bivariate fluorescence activated flow sorting followed by degenerate oligonucleotide-primed PCR (DOP-PCR). Painting of rabbit probes to human chromosomes and vice versa allowed a detailed analysis of the homology between these species. All rabbit chromosome paints, except for the Y paint, hybridized to human chromosomes. All human chromosome paints, except for the Y paint, hybridized to rabbit chromosomes. The results obtained revealed extensive genome conservation between the two species. Rabbit chromosomes 12, 19 and X were found to be completely homologous to human chromosomes 6, 17 and X, respectively. All other human chromosomes were homologous to two or sometimes three rabbit chromosomes. Many conserved chromosome segments found previously in other mammals (e.g. cat, pig, cattle, Indian muntjac) were also found to be conserved in rabbit chromosomes.

Rabbit calcium-sensing receptor (CASR) gene: chromosome location and evidence for related genes

<abstitle>. Diverse cellular functions are regulated by the calcium-sensing receptor, encoded by the CASR gene, which plays an important role in calcium homeostasis. Here we provide the sequence for exon VII of the rabbit CASR gene and show that it is 91% identical to the human gene at the nucleotide level, and 95% identical at the amino acid level. The gene was mapped by fluorescence in situ hybridization, using a cosmid isolated from a genomic library, to chromosome 14q11 and this was confirmed independently by PCR amplification of flow sorted chromosomes. In addition, the cosmid detected sites with lower frequencies on four other chromosomes: 3q, 5p, 8p, and 13p. Two of these sites (5p and 13p) were also detected by a related but unidentical cosmid, and map to regions that are homologous to the mouse calcium-sensing receptor related sequences (Casr-rs); suggesting that they may represent CASR-related sequences in the rabbit. The data support the presence of a family of genes related to the calcium-sensing receptor in the G-protein coupled receptor (GPCR) superfamily, as well as extend the existing knowledge of homology for several human and rabbit chromosomes.

Localization of the α-like globin gene cluster to region q12 of rabbit chromosome 6 by in situ hybridization

The rabbit ( Oryctolagus cuniculus) α-like globin gene cluster (HBAC) contains several block duplications of ζ-, α-, and θ-globin genes. Using in situ hybridizations to metaphase chromosome spreads, the gene cluster has been mapped to region q12 of chromosome 6. Given that human HBAC maps to the short arm of chromosome 16, the mapping of rabbit HBAC to 6q12 confirms the assignment of homology between OCU6q and HSA16p based on similarities of chromosomal banding patterns. In both species, HBAC is in a very G+C-rich region within the most distal band of the chromosome.

Subfamily relationships and clustering of rabbit C repeats.

C repeats constitute the predominant family of short interspersed repeats (SINEs) in the rabbit genome. Determination of the nucleotide sequence 5' to rabbit zeta-globin genes reveals clusters of C repeats, and analysis of these and other sequenced regions of rabbit chromosomes shows that the C repeats have a strong tendency to insert within or in close proximity to other C repeats. An alignment of 44 members of the C repeat family shows that they are composites of different sequences, including a tRNA-like sequence, a conserved central core, a stretch of repeating CT dinucleotides, and an A-rich tract. Cladograms generated by both parsimony and cluster analysis subdivide the C repeats into at least three distinct subfamilies. Nucleotides at sites diagnostic for subfamilies appear to have changed in a punctuated and progressive manner during evolution, indicating that a limited number of progenitors have given rise to new repeats in waves of dispersion. C repeats that insert into preexisting C repeats belong to subfamilies that are proposed to have been propagated more recently; hence, these data support the model of dispersion in successive waves. The divergence among the oldest group of C repeats is greater than that observed for the analogous Alu repeats in humans, indicating that rabbit C repeats have been propagating longer than human Alu repeats. The improved consensus sequence for these repeats is similar to that of the predominant artiodactyl SINE in both the tRNA-like region and a central region. Because members of different subfamilies cross-hybridize very poorly, hybridization data with representatives of each subfamily provide a new minimal estimate, 234,000, for the copy number of C repeats in the rabbit haploid genome, although it is likely that the actual value is closer to 1 million.

Localization of the beta-like globin gene cluster and the genes for parathyroid hormone and c-Harvey-ras 1 to region q14----q21 of rabbit chromosome 1 by in situ hybridization.

The rabbit beta-like globin gene cluster (HBBC), comprised of epsilon-, gamma-, delta-, and beta-globin genes (HBE, HBG, HBD, and HBB, respectively), has been mapped to chromosome 1, region q14----q21, by in situ hybridization using probes for rabbit HBE and HBG. Probes for the human parathyroid hormone gene (PTH) and the Harvey-ras 1 protooncogene (HRAS1) also localize to this region by in situ hybridization. Thus, these genes are syntenic in lagomorphs as well as four other mammalian orders (primates, rodents, carnivores, and artiodactyls). The mapping data in rabbits provide further evidence that this synteny is strongly conserved in the evolution of mammalian chromosomes.

Mapping of the creatine kinase M gene to 19q11----q12 in the rabbit genome.

The chromosomal localization of the gene for creatine kinase M has been determined to be on rabbit chromosome 19 at q11----q12 by in situ molecular hybridization. The results show significant cross-hybridization of the creatine kinase, muscle (CKMM) probe to the previously mapped creatine kinase, brain (CKBB) locus at 20q13----qter, and therefore provide independent support for the localization of CKBB at that site.

Localization of the KRAS2 oncogene in the domestic rabbit (Oryctolagus cuniculus).

The KRAS2 gene was localized in the rabbit by chromosomal in situ hybridization, using a 3H-labeled human cDNA probe. There were 201 silver grains on 144 metaphase spreads; 12.9% of the grains resided on chromosome 16, and 54% of these grains were located close to the centromere at 16p11----q11. Statistical analysis indicated that labeling at this region represents a significant deviation from a random distribution and thus provided evidence for the assignment of KRAS2 to 16p11----q11. In addition to the predominant labeling site on 16, there was a positive signal at the telomere of 9q, possibly representing a sequence of another member of the ras family. Our assignment of KRAS2 to rabbit chromosome 16 strengthens the argument that a fragment on this chromosome is homologous to one on human chromosome 12, which bears the KRAS2 locus.

The high-resolution GTG-banding pattern of rabbit chromosomes.

A cell synchronization technique allowed the high-resolution GTG-banding pattern of rabbit chromosomes to be determined. A karyotype of the late-prophase 622-band stage is presented.

Chromosomal Location of Immunoglobulin Genes: Partial Mapping of These Genes in The Rabbit and Comparison With 1g Genes Carrying Chromosomes of Man and Mouse

This chapter discusses the chromosomal location of immunoglobulin genes. The chromosomal localization of Ig genes in man and mouse is firmly established. The results with mouse–rabbit hybridomas indicates that it is possible to localize Ig genes in rabbit chromosomes, although these hybridomas are unstable and do not allow correlations to be made between enzyme gel electrophoresis of biochemical markers and chromosomal segregation. Rabbit chromosomes are especially suitable for comparison with human chromosomes. Banding similarities for Ig heavy chain genes carrying chromosomes in the three species examined in the chapter extend to most of the chromosome. In addition, Genes for Ig heavy chains can be definitively assigned to the homoeologous region of human chromosome 14, mouse chromosome 12, and rabbit chromosome 16. The mapping of IGH genes in these three species is in agreement with chromosome banding similarities and the genes can confidently be assigned to a specific band located at the distal part of these chromosomes.

The gene map of the rabbit (Oryctolagus cuniculus L.) I. Synteny between the rabbit gene loci coding for HPRT, PGK, G6PD, and GLA: their localization on the X chromosome.

A preferential loss of rabbit chromosomes was observed in 20 independent rabbit/hamster hybrid clones. Sixteen of these clones were analyzed for the enzymatic markers known to be X-linked in many species: HPRT, G6PD, PGK, GLA. These markers were shown to be syntenic, and the genes coding for them were localized on the rabbit X chromosome.

Identification and characterization of rabbit-mouse hybridomas secreting rabbit immunoglobulin chains.

Standard cell-fusion techniques have been used to generate hybrid cells from rabbit spleen cells and mouse myeloma cell lines. The hybrids were selected for secretion of rabbit immunoglobulin. Detailed allotype analyses were carried out for 189 cell lines found to be immunoglobulin positive: 1 produced an intact immunoglobulin molecule with antibody activity, 143 produced rabbit light (L) chains, 36 produced rabbit heavy (H) chains, and 9 cell lines gave negative results in tests for group a and b allotypes. Fusions with a nonproducing murine myeloma cell line (SP-2) yielded only L chain-secreting hybrids, whereas 27% of hybrids resulting from fusion with an L chain-producing line (PU) secreted rabbit H chains paired with mouse L chains. Several of the hybridomas have maintained the ability to produce rabbit immunoglobulin chains in culture for almost 1 year and can be propagated as ascites tumors in athymic (nude) mice. Cytogenetic analyses have detected no rabbit chromosomes in the stable hybrid cell lines.

Differential staining and segregation of parental chromosomes in mouse-rabbit hybridomas

Hoechst 33258 fluorescent staining can be coupled with G-banding to identify the chromosomal contribution of each parent in mouse-rabbit hybridomas. A fast and essentially complete segregation of rabbit chromosomes is obtained in these cells. The rabbit X chromosome is preferentially maintained in media imposing HGPRT activity for cell growth. Mouse-rabbit hybridomas, some of which secrete rabbit immunoglobulin chains, should be a convenient material for the identification of chromosomes governing rabbit Ig chain synthesis.

DNA measurements of mitotic chromosomes of the rabbit (Orytolagus cuniculus).

DNA cytophotometry was used to obtain the relative DNA content of mitotic chromosomes of Orytolagus cuniculus. DNA ranking of the rabbit chromosomes is presented, and related to the quinacrine and Giemsa-banded karyotype. In addition, the relative DNA content of the short and long arms of each chromosome was calculated and the DNA-based centromeric index, (i.e., the ratio of long-arm DNA to total chromosomal DNA) determined. The Y chromosome is clearly a submetacentric chromosome on the basis of the DNA measurements.

Simple chromosome banding technique for farm animal investigations

For routine cytogenetic investigations, a simple banding technique on chromosomes is described. Used on different cell material, a visible banding appearance is produced which makes the typing of chromosomes precise and fast. On 2 examples of cattle and rabbit chromosomes, the identification of a centric fusion and a trisomic is shown.