Localization of the nucleolar organizer by computer-aided analysis of a variant no. 21 in a human isolate

Summary A variant chromosome no. 21 consisting of two stalks and two satellites in tandem was detected during a survey of a human isolate. The variant segregated in three generations of a large kindred. One male had the variant no. 21, a metacentric Y, and a 47, XXY complement; however, no other evidence of chromosomal nondisjunction was found. Computer-aided analysis of sequentially stained variant no. 21 chromosomes indicated that silver-stained material corresponded to the proximal stalk region (as defined defined by Giemsa). These data support the hypothesis that human nucleolar organizers are localized to the stalks of acrocentric chromosomes.     

The isolation of IS1 and IS2 DNA

Summary DNA of the IS-elements IS1 and IS2 was prepared by digestion of appropriate heteroduplex molecules with endonuclease S1, followed by sucrose gradient centrifugation or gel electrophoresis. The material obtained is homogeneous with regard to size. The length of IS1 DNA is 820±65 nucleotides, the length of IS2 DNA is 1.350±70 nucleotides. IS1 DNA is not cleaved by the restriction endonucleases Eco R1, Hind II or Hind III. IS2 DNA is cleaved once by each of the two latter enzymes. The buoyant density determined by equilibrium centrifugation of Hg-complexes in Cs₂SO₄ corresponds to a GC content of approximately 50%. Labelling with polynucleotide kinase indicates that both IS DNA's have a guanosyl residue at both of their 5-termini.     

The effect of ecdysterone on nonhistone proteins in salivary gland chromosomes of Sciara coprophila.

Synthesis and transport of proteins to the cell nucleus during puff induction was studied in S. coprophila. Changes in grain distribution along chromosomes (L-methionine [35S] incorporation into protein) were correlated with puffs induced by ecdysterone in vitro; A pattern of specific labelling at the sites of incipient puffs was noted within 2 h after the addition of the hormone, i.e. grains on the chromosomes were in clusters, characteristic for this time point and not seen in the controls (where only non-specific labeling was noted 0-4 h). Characteristic chromosomal puffs appeared between 3-4 h after the addition of ecdysterone. It was concluded that during ecdysterone-induced puff formation in salivary gland chromosomes, proteins which had been previously synthesized were selectively transported from the cytoplasm to specific sites on the chromosomes.     

A 3'-deoxymononucleotide-producing nuclease from the marine sponge Verongia aerophoba. I. Purification.

A four-step procedure for purification of a nuclease from the keratinous sponge Verongia aerophoba is described. The extracted material is lyophilized, acidified, and subjected to chromatography on Sephadex, hydroxyapatite, and phosphocellulose. The nuclease is purified about 1,000-fold from the crude extract and approximately 1,600-fold from concomitant acid RNase. Phosphodiesterase is lost after chromatography on Sephadex. The purified enzyme solution contains one single activity as determined by polyacrylamide gel electrophoresis.     

A statistical study of the interspike-interval distribution of cortical neurons]

Spontaneous activity was recorded extracellularly by glass microelectrodes from 54 neurons of the Gyrus sigmoideus posterior of unnarcotized and gallamine-immobilazed cats, and the sequential and nonsequential interspike-interval histograms were determined using the multi-channel analyzer CAT 400 C. The interval distributions were characterized by graphic criteria, and it was attempted to describe these distributions mathematically by four biparametric distributions, the Weibull, lognormal, gamma and normal distributions. 80% of the frequency distributions of type I (exponential), II (left skew, gamma-similar) and IV (almost symmetrical) could be assigned to these distributions, namely 43% of the lognormal distribution, 32% of the Weibull distribution, and 5% of the gamma distribution. The interval histograms of the type III (left skew, steep) and V (bimodal) could not be described by any of the distributions selected.     

TBX2 acts as a potent transcriptional silencer of tumour suppressor genes through interaction with the CoREST complex to sustain the proliferation of breast cancers

Chromosome 17q23 amplification occurs in 20% of primary breast tumours and is associated with poor outcome. The TBX2 gene is located on 17q23 and is often over-expressed in this breast tumour subset. TBX2 is an anti-senescence gene, promoting cell growth and survival through repression of Tumour Suppressor Genes (TSGs), such as NDRG1 and CST6. Previously we found that TBX2 cooperates with the PRC2 complex to repress several TSGs, and that PRC2 inhibition restored NDRG1 expression to impede cellular proliferation. Here, we now identify CoREST proteins, LSD1 and ZNF217, as novel interactors of TBX2. Genetic or pharmacological targeting of CoREST emulated TBX2 loss, inducing NDRG1 expression and abolishing breast cancer growth in vitro and in vivo. Furthermore, we uncover that TBX2/CoREST targeting of NDRG1 is achieved by recruitment of TBX2 to the NDRG1 promoter by Sp1, the abolishment of which resulted in NDRG1 upregulation and diminished cancer cell proliferation. Through ChIP-seq we reveal that 30% of TBX2-bound promoters are shared with ZNF217 and identify novel targets repressed by TBX2/CoREST; of these targets a lncRNA, LINC00111, behaves as a negative regulator of cell proliferation. Overall, these data indicate that inhibition of CoREST proteins represents a promising therapeutic intervention for TBX2-addicted breast tumours.     

Preparation and characterization of insulin of carp (Cyprinus carpio).

Insulin of carp (Cyprinus carpio) was isolated and crystallized. The insulin was biologically active in two tests; it decreased the blood glucose level and stimulated 14CO2-formation from glucose. The chemical properties are similar to those of insulins from other species. The insulins of carp and of mammals differ greatly immunologically. Antibodies against carp insulin crossreact with carp proinsulin.