A functional splice site in the 5'' untranslated region of a zein gene.

Zein genes, the genes coding for the zein storage proteins of maize, have a unique gene structure where at least two promoters lie upstream of the coding region. Between the P1 promoter (900 base pairs upstream of the coding region) and the translation initiation AUG codon are 18 short reading frames. A discrepancy between the signals obtained by S1-mapping and primer extension and the DNA sequence in the region of one of these signals suggests the presence of a 3' splice site lying 40 nucleotides upstream of the coding region. A splicing event removing all of the short reading frames from the mRNA transcribed from the P1 promoter would bring this mRNA into a translatable form. Further evidence for a functional 3' splice site has been obtained from sequencing of primer extension products and in vitro splicing of a hybrid intron in the HeLa cell in vitro splicing system.     

Crystal and solution structures of the oligonucleotide d(ATGCGCAT)2: a combined X-ray and NMR study.

A combined crystal-structure determination and NMR analysis of the octanucleotide d(ATGCGCAT)2 is reported. The X-ray analysis shows that the structure is A-form duplex in crystal state. The NMR study shows that in solution this sequence is B-type. The conformational results from each technique are presented in detail. The implications of these findings in terms of conformational flexibility and ligand binding are discussed.     

Risk of nonocular cancer in first-degree relatives of retinoblastoma patients

Summary The increased risk of nonocular cancer seen consistently in studies of survivors of retinoblastoma may be caused in part by the presence of a retinoblastoma gene that also predisposes to other cancers. It has been claimed that this gene also increases the risk for cancer among unaffected relatives of genetic retinoblastoma probands. We report here a population-based study of the risk of nonocular cancer in parents and siblings of persons notified to the Danish Cancer Registry with retinoblastoma during 1943–84. No excess was observed among first degree relatives of 61 genetic retinoblastoma probands, whereas a slight (10%) excess was seen among the parents of 115 nongenetic probands. The latter was the result of significant excesses of malignant melanoma (4 observed, 0.4 expected), multiple myeloma (2 observed, 0.2 expected) and osteogenic sarcoma (1 observed, 0.03 expected). The observed risk pattern cannot be explained by the presence of the retinoblastoma gene.     

Damage and recovery of coral reefs affected by El Niño related seawater warming in the Thousand Islands,Indonesia

Extensive coral bleaching occurred during sea-water warming (as a result of the 1982/3 El Niño Southern Oscillation event) in 1983 on the shallow reefs in the Java Sea. Mean seawater temperatures rose by 2–3° C over a six month period with values greater than 33° C being recorded between 1200–1500 h. As many as 80–90% of corals died on the reef flats at the study sites, with the major casualties being branching species in the genera Acropora and Pocillopora. Five years after the event the community structure of the study sites has recovered significantly, though coral cover is still 50% of its former level. Contrasting patterns of recovery at two selected sites, in close proximity to each other, are discussed.     

Actigraphy: A Means of Assessing Circadian Patterns in Human Activity

-Twenty-three diurnally active (0705-2333), healthy persons between 22 and 54 yrs of age and without history of sleep abnormality were monitored continuously for 120 consecutive hr (five days) by wrist actigraphy. Circadian rhythms of high amplitude were detected by cosinor analysis for each participant and for the groups of 10 males and 13 females with the average span of heightened activity timed between ∼1330 and 1605. The circadian peak-trough difference in wrist movement was marked, equalling aproximately 75% of the 24-hr mean level. In 19 of 23 participants, the 24-hr mean of wrist activity varied between 140-180 movements/min, with four persons exhibiting lesser means of 110-140 movements/min. With respect to the daytime span of activity, the mean wrist movement of individual participants ranged from 155-265 movements/min, with the majority (20/23) varying between 185-245 movements/min. During nocturnal sleep the mean wrist activity level was quite low, varying between individuals from 5 to 25 movements/min for 21 of 23 persons. Wrist actigraphy proved to be well-accepted and was a most reliable means of monitoring aspects of body movement during activity and sleep in ambulatory persons adhering to usual life habits and pursuits.     

Low frequency Raman spectra of Z-DNA

We have performed a Raman study of the low frequency modes in three oligo- and polynucleotides in Z-conformation, and we compare the spectra of these samples to those of two polynucleotides in B-conformation. In Z-DNA we find 5 intrahelical modes below 200 cm-1, in addition to the interhelical mode near 30 cm-1 which is only observed in crystalline samples. The most prominent intrahelical mode has a frequency of about 105 cm-1, close to the frequency of the strongest intrahelical mode in A-and B-DNA. The sequence dependence of the frequency of this mode is considerably larger than for the same mode in B-DNA. The other modes are less pronounced, and their frequency variations with base sequence are within the experimental accuracy.     

Amylase gene expression in intraspecific and interspecific somatic transformants of Drosophila.

The Amylase locus in Drosophila melanogaster normally contains two copies of the structural gene for alpha-amylase, a centromere-proximal copy, Amy-p, and a distal copy, Amy-d. Products of the two genes may display discrete electrophoretic mobilities, but many strains known to carry the Amy duplication are characterized by a single amylase electromorph, e.g., Oregon-R, which produces the mobility variant AMY-1. A transient expression assay was used in somatic transformation experiments to test the functional status of the Amy genes from an Oregon-R strain. Plasmid constructs containing either the proximal or distal copy were tested in amylase-null hosts. Both genes produced a functional AMY-1 isozyme. Constructs were tested against an AMY-3 reference activity produced by a coinjected plasmid that contains the Amy-d3 allele from a Canton-S strain. With reference to the internal control, the Amy-p and Amy-d genes from Oregon-R expressed different relative activity levels for AMY-1 in transient assays. The transient expression assay was successfully used to test the functional status of Amy-homologous sequences from strains of other species of Drosophila characterized by a single amylase elctromorph, namely, Drosophila pseudoobscura ST and Drosophila miranda S 204. The amylase-null strain of D. melanogaster provided the hosts for these interspecific somatic transformation experiments.     

Differential methylation of the hypervariable locus DXS255 on active and inactive X chromosomes correlates with the expression of a human X-linked gene

Consistent differences in methylation of particular cytosine residues in the DNA of active and inactive X chromosomes can be used for rapid, direct analysis of X-inactivation patterns in different female tissues. We have studied methylation of the highly polymorphic DXS255 locus in tissues from patients with deficiency of the E1 alpha subunit of the pyruvate dehydrogenase complex in whom the results can be correlated directly with total enzyme activity, levels of immunoreactive protein, and patterns of cell mosaicism. The results confirm that methylation of the DXS255 locus correlates with X-chromosome expression. In patients and normal controls, the pattern of X inactivation varied widely from tissue to tissue and often deviated markedly from a 50:50 proportion. These deviations are likely to reflect small numbers of tissue-specific stem cells at the time of random X inactivation and cannot be taken alone as evidence for selection or "nonrandom" inactivation.     

Localization of the Miller-Dieker critical region is proximal to locus D17S34 (p144D6) in 17p13.3

A child with normal growth and development and the abnormal karyotype 46,XY,17ps, was analyzed using molecular probes localized to 17p13. The results indicated the presence of two copies of the probes YNZ22.1 (D17S5) and YNH37.3 (D17S28), previously shown to be deleted in all Miller-Dieker (MDS) patients studied. However, the patient was hemizygous for probe p144D6 (D17S34), which is absent in approximately 75% of the MDS patients. As the patient is active at 9 months of age, with no clinical signs of MDS, the results confirm that the absence of locus D17S34 does not lead to the phenotypic expression of MDS. Furthermore, this deletion should assist in defining the distal limits of this contiguous gene syndrome.     

Brain-derived neurotrophic factor increases survival and differentiated functions of rat septal cholinergic neurons in culture

Brain-derived neurotrophic factor (BDNF) was found to promote the survival of E17 rat embryo septal cholinergic neurons in culture, as assessed by a histochemical stain for acetylcholinesterase (AChE). A 2.4-fold increase in neuronal survival was achieved with 10 ng/ml BDNF. After initial deprivation of growth factor for 7 days, BDNF failed to bring about this increase, strongly suggesting that BDNF promotes cell survival and not just induction of AChE. BDNF was also found to increase the levels of cholinergic enzymes; choline acetyltransferase (ChAT) and AChE activities were increased by approximately 2-fold in the presence of 50 ng/ml BDNF. BDNF produced a 3-fold increase in the number of cells bearing the NGF receptor, as detected by the monoclonal antibody IgG-192. Although NGF had no additive effect with BDNF in terms of neuronal survival, suggesting that both act on a similar neuronal population, the combination of both produced an additive response, approximately a 6-fold increase, in ChAT activity.