Nucleotide sequence of the BALB/c mouse beta-globin complex

The nucleotide sequence of 55,856 base-pairs containing all seven beta-globin homologous structures from chromosome 7 of the BALB/c mouse is reported. This sequence links together previously published sequences of the beta-globin genes, pseudogenes and repetitive elements. Using low stringency computer searches, we found no additional beta-globin homologous sequences, but did find many more long interspersed repetitive sequences (L1) than predicted by hybridization. L1 is a major component of the mouse beta-globin complex with at least 15 elements comprising about 22% of the reported sequence. Most open reading frames greater than 300 base-pairs in the cluster overlap with L1 repeats or globin genes. Polypurine, polypyrimidine and alternating purine/pyrimidine tracts are not evenly dispersed throughout the complex, but they do not appear to be excluded from or restricted to particular regions. Several regions of intergenic homology were detected in dot-plot comparisons of the mouse sequence with itself and with the human beta-globin sequence. The significance of these homologies is unclear, but these regions are candidates for further study in functional assays in erythroid cell lines or transgenic animals.     

Locations of three repetitive sequence families found in BALB/c adult beta-globin clones.

Three different repeat sequences have been mapped within the cloned EcoRI fragments that contain the adult beta-globin genes from the BALB/c (Hddd) mouse. One sequence, "a", occurs 1.5-2 kb 3' to the beta-major gene. A second, "b", is found 4kb 5' and 7.5kb 3' to the beta-minor gene. The 14kb EcoRI fragment bearing the beta-minor gene carries at least one additional repetitive element, "c". Probing a BALB/c DNA library with each repeat has demonstrated that these sequences are moderately to highly repetitive and are extensively interspersed with each other throughout the genome. In addition, repeats "a" and "b" are preferentially found in satellite and main-band DNa, respectively. The occurrence of these repeats elsewhere in the beta-globin cluster was demonstrated by probing the non-adult globin clones with each repeat. The arrangement of these repeats around the non-adult genes is 5'-"b"-"b"-epsilon y-beta hl-beta h2-"c"-beta h3-3'. Probing the C57BL/10 (Hbbs) adult gene clones with these repeats demonstrated that the distribution of these sequences in the adult region of these two haplotypes is essentially the same.     

Relationship between DNA replicon size and SCE induction in BALB/c and BALB/Mo mouse lymphocytes

We studied the DNA replicon size in BALB/c and BALB/Mo mouse lymphocytes by the method of bromodeoxyuridine photolysis. After treatment of the BALB/Mo lymphocytes in vitro with mitomycin C, the average DNA replicon size appeared to be significantly smaller than that observed in BALB/c lymphocytes treated similarly. In these conditions an increased susceptibility to SCE induction in BALB/Mo lymphocytes had been observed. In the presence of both mitomycin C and cordycepin (an antiviral drug), both the DNA replicon size and the SCE frequency returned to normal values.     

The molecular organization of the beta-globin complex of the deer mouse, Peromyscus maniculatus

Recombinant DNA clones have been isolated that contain 80 kb of the beta-globin complex from the deer mouse, Peromyscus maniculatus. Comparisons of this complex with that from the laboratory mouse, Mus domesticus (with an order 5'-Hbby, Hbb-bhO, Hbb-bhl, Hbb-bh2, Hbb-bh3, Hbb-bl, Hbb-b2 3') highlight organizational trends in the beta-globin complex since the two species diverged. Unlike other mammals studied thus far, the deer mouse possesses three adult genes. Partial sequence analysis indicates that each of the three adult genes is intact and hence may be functional. Hybridization of one of the two Mus pseudogenes, Hbb-bh3, to genomic blots from Peromyscus reveals that it has a homologous counterpart in Peromyscus. Homologous genes to the two gamma-like Mus genes, Hbb-bhO and Hbb-bhl, are also found in Peromyscus. The strong hybridization between the Hbb-bhl genes and significant nucleotide similarity between the Hbb-bhO genes suggest that both pairs are important for the ontogeny of these mice although no known product has been identified for the Hbb-bhO genes. The presence of Hbb-bhO and Hbb-bhl in Peromyscus suggests that the duplication that created this related gene set occurred before the two lineages diverged. A single gene for Hbb-y has been isolated from Peromyscus. The adult region in Peromyscus has undergone significant divergence from the same region in Mus, having three rather than two adult genes, the acquisition of at least 15 kb of extra DNA relative to Mus, and possibly the loss of the Hbb-bh2 pseudogene. The nonadult region of the complex, in contrast, contains the same set of genes apparently distributed over the same amount of DNA as in the Mus beta- globin complex. This observation suggests that the embryonic region of the complex is more evolutionarily stable than the adult region.      

Organization of mouse mammary tumor virus-specific DNA endogenous to BALB/c mice.

We used restriction endonucleases to prepare physical maps of the mouse mammary tumor virus (MMTV)-specific DNA endogenous to the BALB/c mouse strain. The mapping was facilitated by the DNA transfer procedure, using complementary DNAs specific for the whole and for the 3' terminus of MMTV RNA to detect fragments containing viral sequences. The strategies used for the arrangement of fragments into physical maps included sequential digestions with two or three enzymes; preparative isolation of EcoRI fragments containing viral sequences; and comparisons of virus-specific fragments derived from the DNA of several mouse strains. Most of the MMTV-related DNA in the BALB/c genome is organized into two units (II and III) which strongly resemble proviruses acquired upon horizontal infection with milk-borne strains of MMTV and other retroviruses. These units contain approximately 6.0 x 10(6) Mr of apparently uninterrupted viral sequences, they bear redundant sequences totaling at least 700 to 800 base pairs at their termini, and the terminal redundancies include sequences derived from the 3' end of MMTV RNA. Units II and III are closely related in that they share 12 of 14 recognition sites for endonucleases, but cellular sequences flanking units II and III are dissimilar by this criterion. The remainder of the MMTV-related DNA endogenous to BALB/c mice is found in a single subgenomic unit (unit I) with a complexity of ca. 2 x 10(6) Mr; the structure of this unit has not been further defined. These results support the hypotheses that endogenous proviruses have been acquired by infection of germinal tissues with MMTV. The physical maps are also useful for identifying the MMTV genomes endogenous to BALB/c mice in studies of the natural history of mammary tumorigenesis.     

Bacterial colonization of the oral cavity of the BALB/c mouse

The acquisition of the human oral bacterial flora follows a relatively well known sequence of succession that can be influenced by various host factors. These factors have not been studied in the mouse. In the present work, we followed the bacterial colonization of the oral cavity of mice from birth, and tested our mouse model for its suitability in studying the influence of weaning and puberty on the indigenous oral bacterial flora. We observed that the first colonizers were staphylococci, followed by lactobacilli. The proportions of these two predominant bacteria fluctuated for a period of 30–50 days, but evolved towards the proportions previously observed among the indigenous bacterial species of 6–8 week-old BALB/c male mice (predominantly Lactobacillus murinus and Staphylococcus aureus). The weaning period significantly altered the equilibrium among the oral bacterial flora. This equilibrium was not significantly modified during puberty. Offprint requests to: M.C. Lavoie     

Thymocyte subpopulations during early fetal development in the BALB/c mouse

Phenotypic analysis of thymocytes during murine fetal development may be of use in determining the pathways of thymocyte differentiation. The expression of the functionally significant molecules Lyt-2 (CD8), L3T4 (CD4), and the TCR has already been described. However, mAb specific for several other murine lymphocyte surface markers are now available and, although these have been used to characterize adult thymocytes, a detailed analysis of fetal thymocytes with these antibodies has not previously been undertaken. In this study, we have used mAb specific for Thy-1, J11d, Pgp-1, and the IL-2R, in addition to those for Lyt-2 and L3T4, to identify subpopulations of early fetal thymocytes. By using two-color flow cytometric analysis of cells obtained from fetal thymuses on sequential days of gestation, we have been able to follow the development of various subpopulations through early fetal ontogeny. Our data indicate that the earlier thymocytes are found in the J11d+/Pgp-1+ subset which is abundant at fetal day 14 but constitute a numerical minority by day 16.     

近交系BALB/c小鼠及先天遗传性白内障突变型BALB/cBk-Cat小鼠的DNA指纹研究

采用人工合成的寡核苷酸探针(GATA)~4|分别与近交系小鼠BALB/c和经10年 30代培育而成的自发突变型近交系先天遗传性白内障BALB/cBk-Cat小鼠进行DNA分杂交,DNA指纹显示:(1)BALB/c小鼠个体之间以及BALB/cBk-C at小鼠个体之间没有差异;(2)BALB/c小鼠与BALB/cBk-Cat小鼠的DNA指纹在23-6kb之间的区域有差异。     

近交系BALB/c小鼠及先天遗传性白内障突变型BALB/cBk-Cat小鼠的DNA指纹研究

采用人工合成的寡核苷酸探针(GATA)~4|分别与近交系小鼠BALB/c和经10年 30代培育而成的自发突变型近交系先天遗传性白内障BALB/cBk-Cat小鼠进行DNA分杂交,DNA指纹显示:(1)BALB/c小鼠个体之间以及BALB/cBk-C at小鼠个体之间没有差异;(2)BALB/c小鼠与BALB/cBk-Cat小鼠的DNA指纹在23-6kb之间的区域有差异。     

Structural organization and biological activity of molecular clones of the integrated genome of a BALB/c mouse sarcoma virus.

BALB/c mouse sarcoma virus (BALB-MSV) is a spontaneously occurring transforming retrovirus of mouse origin. The integrated form of the viral genome was cloned from the DNA of a BALB-MSV-transformed nonproducer NRK cell line in the Charon 9 strain of bacteriophage lambda. In transfection assays, the 19-kilobase-pair (kbp) recombinant DNA clone transformed NIH/3T3 mouse cells with an efficiency of 3 X 10(4) focus-forming units per pmol. Such transformants possessed typical BALB-MSV morphology and released BALB-MSV after helper virus superinfection. A 6.8-kbp DNA segment within the 19-kbp DNA possessed restriction enzyme sites identical to those of the linear BALB-MSV genome. Long terminal repeats of approximately 0.6 kbp were localized at either end of the viral genome by the presence of a repeated constellation of restriction sites and by hybridization of segments containing these sites with nick-translated Moloney murine leukemia virus long terminal repeat DNA. A continuous segment of at least 0.6 and no more than 0.9 kbp of helper virus-unrelated sequences was localized toward the 3' end of the viral genome in relation to viral RNA. A probe composed of these sequences detected six EcoRI-generated DNA bands in normal mouse cell DNA as well as a smaller number of bands in rat and human DNAs. These studies demonstrate that BALB-MSV, like previously characterized avian and mammalian transforming retroviruses, arose by recombination of a type C helper virus with a well-conserved cellular gene.     

DNA sequence organization in the soybean plant

The arrangement of repetitive and nonrepetitive DNA sequences in the soybean genome was ascertained by a comparison of the reassociation kinetics of short (250 nucleotides) and long (2700 nucleotides) DNA fragments, the size distribution of S-1 nuclease resistant repetitive duplexes, and a direct assay of the spectrum of DNA sequences present on long DNA fragments enriched in repetitive DNA. These measurements reveal the following: (1) The 1N genome size of the soybean plant is 1.97 pg. (2) Approximately 40% of the soybean genome consists of nonrepetitive or single-copy DNA sequences, while 60% is repetitive DNA. (3) The repetitive DNA is partitioned into three discrete classes termed very fast, fast, and slow, containing DNA sequences repeated an average of 290,000, 2800, and 19 times each. (4) Approximately 35–50% of the soybean genome is arranged in a short-period interspersion pattern of 250 nucleotide slow sequences and single-copy DNA averaging up to 2700 nucleotides in length. (5) From 30% to 45% of the soybean genome is organized into long stretches of repetitive DNA at least 1500 nucleotides in length. (6) Minimal interspersion of repetitive sequence classes occurs in soybean DNA.These experiments were supported by NSF Grants BMS74-21461 and PCM76-24593 and were conducted while the author was in the Department of Biology, Wayne State University, Detroit, Michigan.     

Nucleotide sequence analysis of the BALB/c murine sarcoma virus transforming gene.

We determined the nucleotide sequence of the v-H-ras-related oncogene of BALB/c murine sarcoma virus. This oncogene contains an open reading frame of 189 amino acids that initiates and terminates entirely within the mouse cell-derived ras sequence. The protein encoded by this open reading frame matches the sequence predicted for the T24 human bladder carcinoma oncogene product, p21, in all but two positions. The presence of a lysine residue in position 12 of BALB/c murine sarcoma virus p21 likely accounts for its oncogenic properties.     

Detection of polymorphism in BALB/c leukemia viruses with mouse antisera.

Antisera produced in mice recognize primarily type-specific antigenic determinants on both the major core protein, p30, and the major envelope proteins, gp70 and p15(E), of the endogenous leukemia viruses (MuLV) of BALB/c mice. Three different mouse sera were investigated in detail. (i) Antisera prepared in C57BL/6 mice against the AKR leukemia K36 reacted with the gp70, p15(E), and p30 proteins of MuLV. Certain pools of the C57BL/6 anti-AKR K36 serum contained antibodies which serologically distinguished the p30 proteins of N-ecotropic, B-ecotropic, and xenotropic BALB/c MuLV. (ii) Antisera prepared in BALB/c mice against the BALB/c sarcoma 1315 contained antibodies that reacted with a type-specific antigen of the 1315 MuLV gp70 that is not found on other BALB/c MuLV. (iii) The normal sera of multiparous BALB/c mice contained antibodies that reacted with gp70 and p15(E) proteins of ecotropic MuLV. Sera from some of these mice contained antibodies that serologically distinguished the gp70 of N-ecotropic and B-ecotropic BALB/c viruses. These results emphasize the utility of mouse antisera in the serological typing of MuLV. Furthermore, the antigenic differences observed in the p30 and gp70 proteins should be of particular use in the future analysis of recombinant BALB/c MuLV.     

The expression of mouse T-cell receptor TCRDV genes in BALB/c spleen

The rearrangement and expression of six different mouse T-cell receptor TCRDV (V) gene subfamilies have been studied in BALB/c mouse spleen. The results show that all the TCRDV gene segments studied can be rearranged and expressed with both the TCRA () and the TCRD () chain. The apparently restricted and separated V gene repertoire for the TCRD and TCRAT-cell receptor may result from thymus and peripheral selection rather than from selective rearrangement in the DNA level. Several J gene segment show how much higher concentration in spleen with TCRDV gene segments, however, these J gen segments do not tend to be located at either end of the J gene cluster.     

The secretion of two sperm maturation-related glycoproteins in BALB/c mouse epididymis

Summary A well-developed Golgi apparatus and rough and smooth endoplasmic reticulum in the principal cells of the mouse epididymis indicate active protein synthesis. Studies have shown that epididymal secretions are essential for sperm maturation. In a previous study, two wheat-germ agglutinin (WGA)-binding glycoproteins, GP-49 and GP-83, were identified on the surface of mature mouse sperm. In this study, synthesis and secretion of these two glycoproteins were investigated. Apparent WGA-binding was found on the stereocilia and in the apical region of principal cells in the corpus and cauda of epididymis. Post-fixation and pre-embedding cytochemical localization revealed that WGA-binding sites were situated in the Golgi apparatus, multivesicular bodies and stereocilia of principal cells. GP-49 and GP-83 were identified in the Nonidet P-40 homogenates of corpus and cauda epididymidis. In the epididymides of which ductuli efferentes had been ligated for more than 4 weeks, no sperm were found in the lumina of epididymal tubules. WGA-binding sites were present in the corpus and cauda; GP-49 and GP-83 were identified in tissue homogenates of the corpus and cauda as well. These findings suggest that GP-49 and GP-83 of mature sperm may be secreted by the principal cells of the corpus and cauda. These two molecules apparently conjugate to sperm whilst sperm transit through the epididymis.     

Genomic organization and nucleotide sequence of a long mosaic repetitive DNA in the mouse genome

A long mosaic repetitive sequence (LMRS) was isolated from a mouse liver genome library using a mouse repetitive DNA as a probe. LMRS exhibits the following features: (1) it is almost 15 kb in length; (2) it is partly organized in tandem array and frequently interrupted by other repeated sequences; and (3) it is located predominantly on the A3 band of the mouse X Chromosome (Chr). One fragment of LMRS (B6) shows restriction fragment length polymorphism (RFLP) between different mouse strains, and is thus potentially useful for mapping studies. The nucleotide sequence confirms a mosaic organization of LMRS which includes three repeats in the 5 part, showing similarity with the 5 end of L1Md-A2, and seven long A+T rich segments in the central part of the element. Our findings suggest that this sequence may have arisen from the duplication of an ancestral motif and has expanded by successive waves of amplification and invasion by foreign sequences.The nucleotide sequence data reported in this paper have been submitted to EMBL and have been assigned the accession number X55036.     

Cloning of a new mouse foetal beta-globin mRNA sequence.

A novel globin cDNA recombinant (pFG5) has been isolated from a 14-15 day Porton mouse foetal liver cDNA library. It codes for a beta-like globin mRNA expressed in foetal liver-derived erythroblasts and erythrocytes but not in adult reticulocytes nor in yolk sac derived nucleated erythrocytes. It is also found in Friend cells induced to differentiate by DMSO. The nucleotide sequence of pFG5 confirms that it does not code for the beta major or beta minor globin chains nor the embryonic epsilon Y2 globin chain; but it is identical to the published partial sequence of the epsilon Y3 globin gene over the region of overlap (78 nucleotides).