Silver staining of proteins in polyacrylamide gels.

During active disease, patients with systemic-onset juvenile chronic arthritis (S-JCA) demonstrate a rise and fall in serum interleukin-6 (IL-6) that parallels the classic quotidian fever. To investigate the possibility that this cytokine profile results from a difference in the control of IL-6 expression, we examined the 5' flanking region of the IL-6 gene for polymorphisms. A G/C polymorphism was detected at position -174. In a group of 383 healthy men and women from a general practice in North London, the frequency of the C allele was 0.403 (95% confidence interval 0.37-0.44). In comparison, 92 patients with S-JCA had a different overall genotype frequency, especially those with onset of disease at < 5 yr of age. This was mainly due to the statistically significant lower frequency of the CC genotype in this subgroup. When comparing constructs of the 5' flanking region (-550-+61 bp) in a luciferase reporter vector transiently transfected into HeLa cells, the -174C construct showed 0.624+/-0.15-fold lower expression than the -174G construct. After stimulation with LPS or IL-1, expression from the -174C construct did not significantly change after 24 h, whereas expression from the -174G construct increased by 2.35+/-0.10- and 3.60+/-0.26-fold, respectively, compared with the unstimulated level. Plasma levels of IL-6 were also measured in 102 of the healthy subjects, and the C allele was found to be associated with significantly lower levels of plasma IL-6. These results suggest that there is a genetically determined difference in the degree of the IL-6 response to stressful stimuli between individuals. The reduced frequency of the potentially protective CC genotype in young S-JCA patients may contribute to its pathogenesis. Similarly the individual's IL-6 genotype may be highly relevant in other conditions where IL-6 has been implicated, such as atherosclerosis.

/pdf/the-effect-of-novel-polymorphisms-in-the-interleukin-6-il-6-1ex1zrvxnz.pdf

The effect of novel polymorphisms in the interleukin-6 (IL-6) gene on IL-6 transcription and plasma IL-6 levels, and an association with systemic-onset juvenile chronic arthritis.

In most higher organisms, DNA is modified after synthesis by the enzymatic conversion of many cytosine residues to 5-methylcytosine. For several years, control of gene activity by DNA methylation has been recognized as a logically attractive possibility, but experimental support has proved elusive. However, there is now reason to believe, from recent studies, that DNA methylation is a key element in the hierarchy of control mechanisms that govern vertebrate gene function and differentiation.

https://science.sciencemag.org/content/sci/210/4470/604.full.pdf

DNA methylation and gene function

A number of individuals with aberrant Y chromosomes have been tested for the presence of Y-chromosome-specific reiterated DNA. These studies locate Y-chromosome-specific reiterated sequences on the long arm of the Y chromosome. Correlation with phenotype and other known Y chromosome markers establish that the Y-chromosome-specific reiterated DNA discussed here has no evident role in male determination.

http://www.pnas.org/content/74/3/1245.full.pdf

Analysis of human Y-chromosome-specific reiterated DNA in chromosome variants.

Huntington's disease (HD) is associated with the expansion of a CAG trinucleotide repeat in a novel gene. We have assessed 360 HD individuals from 259 unrelated families and found a highly significant correlation (r = 0.70, p = 10(-7)) between the age of onset and the repeat length, which accounts for approximately 50% of the variation in the age of onset. Significant associations were also found between repeat length and age of death and onset of other clinical features. Sib pair and parent-child analysis revealed that the CAG repeat demonstrates only mild instability. Affected HD siblings had significant correlations for trinucleotide expansion (r = 0.66, p < 0.001) which was not apparent for affected parent-child pairs.

The relationship between trinucleotide (CAG) repeat length and clinical features of Huntington's disease

Suppression of human nucleolus organizer activity in mouse-human somatic hybrid cells.

Clinical data are available for 23 cases with the karyotype 46 Dqor 46 Dr. Seventeen cases have been published, data on four were obtained through personal communication, and two have been studied in our laboratory. Autoradiographic identification of a ring D chromosome has previously been made in six of these cases. In five, the ring originated from a chromosome 13 (Bloom et al 1967; Gerald et al. 1967; Hollowell et al. 1967; Niebuhr and Mikkelsen, personal communication [1968]; and Stimson and Hecht, personal communication [1968]). In one case (Sparkes et al. 1967), the ring apparently originated from a chromosome 14. The authors postulated that their case represented a unique syndrome characterized by absent thumbs and suggested that the same syndrome was present in two cases reported earlier, each having an unidentified ring D chromosome (Bain and Gauld 1963; Adams 1965). The patient studied by Sparkes et al. (1967) had microcephaly, hypertelorism, a broad nasal bridge, ocular dystrophy, and large ears. These features are characteristic of the "Dr" syndrome which Lejeune et al. (1968) proposed as antithetical to trisomy 13. Congenital anomalies typical of the "Dr" syndrome have also been observed in individuals with aDqchromosome.Three of these patients had hypoplastic thumbs (Thompson and Lyons 1965; Laurent et al. 1967; Hollowell, personal communication [1969]). The Dqchromosome originated from a chromosome 13 in two cases where terminal labeling studies were performed (Gey, personal communication [1968]; Hollowell, personal communication [1969]). The present paper concerns two clinically similar cases which resemble others with the karyotype 46 Dqor 46 Dr. Case 1 has a small deletion from a distal segment of the long arm of a D-group chromosome, and case 2 has a ring D chromosome. We have identified each abnormal chromosome autoradiographically as a chromosome 13. We postulate that our cases illustrate one distinct chromosome-deletion syndrome caused by partial monosomy for a distal segment of the long arm of chromosome 13.

/pdf/the-13q-deletion-syndrome-4le9wctsh8.pdf

The 13q-deletion syndrome.

Methaphase chromosomes from karyotypically normal adult humans (three males, six females) and one male with a 13p - chromosome were stained by quinacrine and then by the Ag-AS silver staining method to reveal nucleolus organizer regions (NORs). Each person had a characteristic number of Ag-stained chromosomes per cell, always fewer than 10. Determination of the mean Ag-size of each chromosome showed that each of the 10 individuals had a unique distribution of Ag-stain. Within each individual, there was some variation from cell to cell in the number of acrocentric chromosomes that were Ag-stained; this was not random, and the same chromosomes (those that had at most a small amount of Ag-stain) tended to be unstained in every cell. Satellite associations were scored on the same cells. Chromosomes that had no Ag-stain were involved in satellite association less than 20% as often as those that had some Ag-stain. Chromosomes that had a small amount of Ag-stain were involved in association about 50% as often as those that had a large amount of stain. Regression analysis of the 50 (of a total of 100) acrocentric chromosomes which could be individually identified by quinacrine markers showed that the frequency with which a chromosome was involved in satellite association was strongly correlated with the amount of Ag-stained material in the NOR.

Frequency of satellite association of human chromosomes is correlated with amount of Ag-staining of the nucleolus organizer region.

Silver staining has been used to detect active nucleolus organizer regions (NOR's). By this criterion six mouse chromosomes, numbers 12, 15, 16, 17, 18 and 19, can have an NOR. The number and distribution of chromosomes with NOR's vary among inbred strains of Mus musculus musculus (C57BL/6J, BALB/cJ, C3H/HeJ and C3H/StCpr1BR) and in M. musculus molossinus. In a musculus X molassinus F1 hybrid, nucleolus organizers from each parent are silver stained.--Chromosomes which have NOR's in diploid cells also show them in tetraploid cells and in established cell lines. The BALB/cJ strain shows Ag-staining of NOR's on chromosomes 12, 15, 18 and occasionally 16. In the RAG cell line, which was derived from BALB/c, active NOR's are seen on 12, 15 and 18, even after these chromosomes have undergone structural rearrangements in the cell line. Some correlation exists between the amount of Ag-stain and the size of a secondary construction region, with a large amount of Ag-stain present on a chromosome which has a prominent secondary constriction. There is no correlation between the amount of Ag-stain and the presence or absence of C-band material.

https://www.genetics.org/content/genetics/86/2/389.full.pdf

O.J. Miller

Papers

Analysis of human Y-chromosome-specific reiterated DNA in chromosome variants.

Suppression of human nucleolus organizer activity in mouse-human somatic hybrid cells.

The 13q-deletion syndrome.

Frequency of satellite association of human chromosomes is correlated with amount of Ag-staining of the nucleolus organizer region.

Nucleolus organizers in Mus musculus subspecies and in the RAG mouse cell line.