Biology Commons^™

Multiple Isoforms Of Gaga Factor, A Critical Component Of Chromatin Structure, C Benyajati, L Mueller, N Xu, M Pappano, J Gao, M Mosammaparast, D Conklin, H Granok, C Craig, Sarah C.R. Elgin

Biology Faculty Research

The GAGA transcription factor of Drosophila melanogaster is ubiquitous and plays multiple roles. Characterization of cDNA clones and detection by domain- specific antibodies has revealed that the 70-90 kDa major GAGA species are encoded by two open reading frames producing GAGA factor proteins of 519 amino acids (GAGA-519) and 581 amino acids (GAGA-581), which share a common N-terminal region that is linked to two different glutamine-rich C-termini. Purified recombinant GAGA-519 and GAGA-581 proteins can form homomeric complexes that bind specifically to a single GAGA sequence in vitro. The two GAGA isoforms also function similarly in transient transactivation assays in tissue …

Social Organization Of Neotoma Micropus, The Southern Plains Woodrat, Sarah A. Conditt, David O. Ribble

Biology Faculty Research

This study described the social organization of Neotoma micropus, the southern plains woodrat, using radiotelemetry. We studied woodrats from September 1994 through April 1995 at the Urban Wilderness Reserve in S Bexar County, Texas. Sixteen individuals (three adult males, 11 adult females, and two subadult males) were radiocollared and located in the evening or early morning during January and February. Seventy-four percent of female radiolocations and 57% of male radiolocations were from their respective nests. No more than one adult individual was observed at any nest at the same time. Males had significantly larger (x = 1899 m^{2 …}

Chromosomes And Expression Mechanisms, Sarah C.R. Elgin, S. P. Jackson

Biology Faculty Research

No abstract provided.

Biology: What One Needs To Know, Ursula Goodenough

Biology Faculty Research

Biology on this planet represents an astonishing experiment in carbon-based chemistry which, over billions of years, has generated billions of species adapted to countless major and minor fluctuations in ecological circumstances. In one sense there is no way to generalize about biology. While biological activities can all be ultimately explained by physical laws (like everything else in the universe), it is the emergent intensely particular properties of organisms that most interest us. This essay represents an attempt to describe some of the more prominent patterns that emerge from the sea of biological particularities, patterns that present many opportunities for religious …

Dna Representation Of Variegating Heterochromatic P-Element Inserts In Diploid And Polytene Tissues Of Drosophila Melanogaster, Lori L. Wallrath, Vamsi P. Guntur, L Rosman, Sarah C.R. Elgin

Biology Faculty Research

Position-effect variegation (PEV) is the mosaic expression of a euchromatic gene brought into juxtaposition with heterochromatin. Fourteen different transformed Drosophila melanogaster lines with variegating P-element inserts were used to examine the DNA levels of these transgenes. Insert sites include pericentric, telomeric and fourth chromosome regions. Southern blot analyses showed that the heterochromatic hsp26 transgenes are underrepresented 1.3- to 33-fold in polytene tissue relative to the endogenous euchromatic hsp26 gene. In contrast, the heterochromatic hsp26 transgenes are present in approximately the same copy number as the endogenous euchromatic hsp26 gene in diploid tissue. It appears unlikely that DNA loss could account …

Heterochromatin And Gene Regulation In Drosophila, Sarah C.R. Elgin

Biology Faculty Research

We have recently learned more about the biochemistry of heterochromatin and about how heterochromatic environments affect gene function. New findings have emphasized the distinctions between telomeric and pericentric heterochromatin in Drosophila and have suggested a mosaic structure within pericentric heterochromatin. Theories concerning the mechanism of inactivation of euchromatic genes in heterochromatic environments have been tested using transgenes inserted into heterochromatin. The current data support a competition/chromatin structure model, in which multiprotein repressor complexes compete with transcriptional activators to assemble an active or inactive chromatin structure.

Position Effect Variegation In Drosophila Is Associated With An Altered Chromatin Structure, Lori L. Wallrath, Sarah C.R. Elgin

Biology Faculty Research

A euchromatic gene placed in the vicinity of heterochromatin by a chromosomal rearrangement generally exhibits position effect variegation (PEV), a clonally inherited pattern showing gene expression in some somatic cells but not in others. The mechanism responsible for this loss of gene expression is investigated here using fly lines carrying a P element containing the Drosophila melanogaster white and hsp26 genes. Following mobilization of the P element, a screen for variegation of white expression recovered inserts at pericentric, telomeric, and fourth chromosome regions. Previously identified suppressors of PEV suppressed white variegation of pericentric and fourth chromosome inserts but not telomeric …

The Religious Dimensions Of The Biological Narrative, Ursula W. Goodenough

Biology Faculty Research

A cell/molecular biologist challenges the thesis that science and religion are two ways of experiencing and interpreting the world and explores instead the possible ways that the modern biological worldview might serve as a resource for religious perspectives. Three concepts—meaning, valuation, and purpose—are argued to be central to the entire biological enterprise, and the continuation of this enterprise is regarded as a sacred religious trust.

This article was originally delivered at the Templeton Symposium,„Science and Religion: Two Ways of Experiencing and Interpreting the World”organized by Zygon: Journal of Religion and Science and the Chicago Center for Religion and Science, 31 …

What Science Can And Cannot Offer To A Religious Narrative, Ursula W. Goodenough

Biology Faculty Research

A molecular/cell biologist offers perspectives on the contributions that the scientific worldview might and might not make to religious though. It is argued that two essential features of institutionalized religions–their historical context and their supernatural orientation—are not addressed by the sciences, nor can the sciences contribute to the art and ritual that elicit states of faith and transcendence. The sciences have, however, important stories (myths) to offer, stories that have the potential to unify us, to tell us what is sacred, what has meaning, and how we might best proceed.

This paper, in slightly different form, was first presented before …

Insensitivity Of The Present Hsp26 Chromatin Structure To A Tata Box Mutation In Drosophila, Quinn Lu, Lori L. Wallrath, P Emanuel, Sarah C.R. Elgin, D Gilmour

Biology Faculty Research

The role of the TATA element in establishing the chromatin structure and inducible transcription of the Drosophila melanogaster hsp26 gene has been analyzed. An hsp26/lacZ fusion gene with a mutant promoter, in which the TATA box sequence TATAAA was changed to CCCAAA, was introduced into Drosophila by P-element transformation. The mutation had little effect on formation of the preset chromatin structure observed prior to induction. However, the mutation dramatically reduced transcription levels following heat shock. Northern analysis indicated that weak, inducible expression of the mutant promoter occurred within the same period of heat shock as for the normal promoter, suggesting …

Creativity In Science, Ursula W. Goodenough

Biology Faculty Research

Creativity is a concept far more often associated with art than with science. The creative dimension of scientific inquiry and practice is described and compared with its artistic counterpart; similarities and differences are analyzed.

She presented this paper at the Thirty-Seventh Annual Star Island Conference of the Institute on Religion in an Age of Science (IRAS), “Creativity, Non-Conformity, and Madness” at Star Island, New Hampshire, 28 July-4 August 1990.

Inconsistent Divergence Of Mitochondrial-Dna In The Spontaneously Hypertensive Rat, Mark L. Johnson, Steve W. Perry, Daniel Ely, Monte E. Turner

Biology Faculty Research

We have recently shown that the spontaneously hypertensive rat (SHR) and the Wistar-Kyoto (WKY) rat differ at a frequency of 1 per 62 bases in their nuclear DNA (Hypertension 1992;19:425-427). Given the origin of these strains this level of divergence was unexpected. To investigate the origin of this nuclear divergence we have examined mitochondrial DNA. Mitochondrial DNA was isolated from SHR and WKY rats, digested with several restriction enzymes, electrophoresed in 1.0% agarose gels, and the fragments visualized with ethidium bromide staining. This approach allowed us to analyze 220 base pairs of mitochondrial DNA. No differences were detected between SHR …

Molecular Cloning Of A Human Homologue Of Drosophila Heterochromatin Protein Hp1 Using Anti-Centromere Autoantibodies With Anti-Chromo Specificity, W Saunders, C Chue, M Goebl, Carolyn Craig, Robert F. Clark, J Powers, J Eissenberg, Sarah C.R. Elgin, N Rothfield, W Earnshaw

Biology Faculty Research

We have identified a novel autoantibody specificity in scleroderma that we term anti-chromo. These antibodies recognize several chromosomal antigens with apparent molecular mass of between 23 and 25 kDa, as determined by immunoblots. Anti-chromo autoantibodies occur in 10-15% of sera from patients with anti-centromere antibodies (ACA). We used anti-chromo antibodies to screen a human expression library and obtained cDNA clones encoding a 25 kDa chromosomal autoantigen. DNA sequence analysis reveals this protein to be a human homologue of HP1, a heterochromatin protein of Drosophila melanogaster. We designate our cloned protein HP1Hs alpha. Epitope mapping experiments using both human and Drosophila …

Heterochromatin Protein 1, A Known Suppressor Of Position-Effect Variegation, Is Highly Conserved In Drosophila, Robert F. Clark, Sarah C.R. Elgin

Biology Faculty Research

The Su(var)205 gene of Drosophila melanogaster encodes heterochromatin protein 1 (HP1), a protein located preferentially within beta-heterochromatin. Mutation of this gene has been associated with dominant suppression of position-effect variegation. We have cloned and sequenced the gene encoding HP1 from Drosophila virilis, a distantly related species. Comparison of the predicted amino acid sequence with Drosophila melanogaster HP1 shows two regions of strong homology, one near the N-terminus (57/61 amino acids identical) and the other near the C-terminus (62/68 amino acids identical) of the protein. Little homology is seen in the 5' and 3' untranslated portions of the gene, as well …

Dispersal In A Monogamous Rodent, Peromyscus Californicus, David O. Ribble

Biology Faculty Research

In view of theoretical interest in the relationships between mating systems and dispersal patterns and the paucity of empirical data on dispersal in monogamous mammals, I studied natal dispersal in the monogamous rodent Peromyscus californicus. Genealogical relationships were determined using fluorescent pigment transfer and DNA fingerprinting, and dispersal distances were determined using dispersal fences and intensive trapping. Minimum dispersal distances were greater for females than for males. Philopatric males (those settling within one home-range diameter of their birth site) tended to be from smaller litters than non-philopatric males. Minimum dispersal distances of males were positively associated with natal litter …

Promoter Sequence Containing (Ct)N.(Ga)N Repeats Is Critical For The Formation Of The Dnase I Hypersensitive Sites In The Drosophila Hsp26 Gene, Qin Lu, Lori L. Wallrath, Barbara D. Allan, R Glaser, J Lis, Sarah C.R. Elgin

Biology Faculty Research

We have analyzed P-element-transformed lines carrying hsp26/lacZ transgenes with various deletions and substitutions within the Drosophila melanogaster hsp26 promoter region in order to identify the sequences required for the formation of the DNase I hypersensitive sites (DH sites). DH sites are generally found associated with promoters and enhancer elements of active and inducible eukaryotic genes, and are thought to be nucleosome-free regions of DNA that interact with regulatory proteins and the transcriptional machinery. There are two major DH sites located within the promoter region of the hsp26 gene, centered at -50 and at -350 (relative to the hsp26 transcription start …

A Histone Variant, H2avd, Is Essential In Drosophila Melanogaster, Angela Van Daal, Sarah C.R. Elgin

Biology Faculty Research

H2AvD, a Drosophila melanogaster histone variant of the H2A.Z class, is encoded by a single copy gene in the 97CD region of the polytene chromosomes. Northern analysis shows that the transcript is expressed in adult females and is abundant throughout the first 12 h of embryogenesis but then decreases. The H2AvD protein is present at essentially constant levels in all developmental stages. Using D. melanogaster stocks with deletions in the 97CD region, we have localized the H2AvD gene to the 97D1-9 interval. A lethal mutation in this interval, l(3)810, exhibits a 311-base pair deletion in the H2AvD gene, which removes …

Genetic-Divergence Between The Wistar-Kyoto Rat And The Spontaneously Hypertensive Rat, Mark L. Johnson, Daniel Ely, Monte E. Turner

Biology Faculty Research

A method of restriction fragment length polymorphism (RFLP) analysis was used to estimate the amount of genetic divergence between the spontaneously hypertensive rat (SHR) strain and the Wistar-Kyoto (WKY) strain. DNA from each strain was digested with eight restriction endonucleases and hybridized with six single copy gene sequences. The number of hybridization bands in each digestion was used to estimate the total number of bases analyzed and RFLPs were scored as single mutations. Divergence was then estimated by dividing the number of mutations by the number of bases analyzed. In a total of 808 bases analyzed in WKY rats, a …

A Drosophila Melanogaster H3.3 Cdna Encodes A Histone Variant Identical With The Vertebrate H3.3, Scott Fretzin, Barbara D. Allan, Angela Van Daal, Sarah C.R. Elgin

Biology Faculty Research

A cDNA encoding an H3.3 histone variant in Drosophila melanogaster predicts a protein with an amino acid (aa) sequence identical with that in vertebrates. The D. melanogaster H3.3 nucleotide (nt) sequence has diverged significantly from that of both the H3.3 gene of vertebrates and the H3.1 gene of D. melanogaster, largely through third nt changes in its codons. The perfect H3.3 aa sequence conservation between organisms as phylogenetically divergent as vertebrates and flies suggests that the H3.3 histone variant itself is an important structural component of chromatin, apart from the value of its replication-independent expression pattern. Keywords: Conserved proteins, amino …

Separate Sex-Influenced And Genetic Components In Spontaneously Hypertensive Rat Hypertension, Monte E. Turner, Mark L. Johnson, Daniel Ely

Biology Faculty Research

Previous results from our laboratory indicated two major genetic components of spontaneously hypertensive rat (SHR) hypertension, an autosomal component and a Y chromosome component. Two new substrains, SHR/a and SHR/y, were developed using a series of backcrosses to isolate each of these components. The SHR/a substrain has the autosomal loci and X chromosome from the SHR strain and the Y chromosome from the Wistar-Kyoto (WKY) rat strain. The SHR/y substrain has only the Y chromosome from the SHR and autosomal loci and X chromosome from the WKY strain. Throughout these breeding programs parents were chosen at random without selection for …

Androgen Receptor And The Testes Influence Hypertension In A Hybrid Rat Model, Daniel Ely, Ron Salisbury, Disha Hadi, Monte E. Turner, Mark L. Johnson

Biology Faculty Research

The objective of this study was to determine if males with a deficient androgen receptor would develop hypertension when crossed with a hypertensive parent. Female King-Holtzman rats (n = 15), heterozygous for the testicular feminization (Tfm) gene, were crossed with male spontaneously hypertensive rats (SHR), and blood pressure was measured weekly from 5-14 weeks in the F1 hybrid males. Approximately 50% of the F1 hybrid males were Tfm males and androgen receptor-deficient, and 50% were normal. Blood pressure in the parent King-Holtzman males, Tfms, and female rats was also followed for the same time period. The F1 normal male hybrids …

A Unique Zinc Finger Protein Is Associated Preferentially With Active Ecdysone-Responsive Loci In Drosophila, S Amero, Sarah C.R. Elgin, A Beyer

Biology Faculty Research

Using an immunochemical approach, we have identified a unique antigen, PEP (protein on ecdysone puffs), which is associated in third-instar larvae with the active ecdysone-regulated loci on polytene chromosomes; PEP is not associated with most intermolt puffs and is found on some, but not all, heat shock-induced puffs. The distribution pattern changes with changing puffing patterns in the developmental program. We have screened an expression library and recovered a cDNA clone encoding PEP. PEP possesses multiple potential nucleic acid- and protein- binding regions: a glycine- and asparagine-rich amino terminus, four zinc finger motifs, two very acidic segments, two short basic …

Hypertension In The Spontaneously Hypertensive Rat Is Linked To The Y-Chromosome, Daniel Ely, Monte E. Turner

Biology Faculty Research

The objective of our study was to determine the genetic influence on blood pressure in spontaneously hypertensive rats (SHR), and normotensive Wistar-Kyoto (WKY) rats using genetic crosses. Blood pressure was measured by tail sphygmomanometry from 8 to 20 weeks of age. Blood pressure was significantly higher from 12 to 20 weeks in the male offspring derived from WKY mothers x SHR fathers as compared with male offspring derived from SHR mothersxWKY fathers (180±4 versus 160±5 mm Hg, /?<0.01). There was no significant difference between the blood pressure of the F, females, further supporting Y chromosome linkage and not parental imprinting. The blood pressure data from F2 males derived from reciprocal crosses of parental strains were consistent with the presence of a Y-Iinked locus, but not with an X-linked locus controlling blood pressure. The data strongly suggest that hypertension in the SHR has two primary components of equal magnitude, one consisting of a small number of autosomal loci with a second Y-linked component.

Chromatin Structure And Gene Activity, Sarah C.R. Elgin

Biology Faculty Research

No abstract provided.

Conservation Of Intron Position Indicates Separation Of Major And Variant H2as Is An Early Event In The Evolution Of Eukaryotes, A Van Daal, E White, Sarah C.R. Elgin, M Gorovsky

Biology Faculty Research

Genomic clones of Drosophila and Tetrahymena histone H2A variants were isolated using the corresponding cDNA clones (van Daal et al. 1988; White et al. 1988). The site corresponding to the initiation of transcription was defined by primer extension for both Drosophila and Tetrahymena genomic sequences. The sequences of the genomic clones revealed the presence of introns in each of the genes. The Drosophila gene has three introns: one immediately following the initiation codon, one between amino acids 26 and 27 (gln and phe), and one between amino acids 64 and 65 (glu and val). The Tetrahymena gene has two introns, …

Optimal Heat-Induced Expression Of The Drosophila Hsp26 Gene Requires A Promoter Sequence Containing (Ct)N.(Ga)N Repeats, R Glaser, Graham H. Thomas, Ester Siegfried, Sarah C.R. Elgin, J Lis

Biology Faculty Research

We report here the analysis of the sequence requirements for the heat-induced expression of the Drosophila melanogaster hsp26 gene using germline transformation. Heat-induced expression is augmented fivefold by a homopurine/homopyrimidine region from -85 to -134 that is devoid of heat-shock elements but contains numerous (dC-dT).(dG-dA) repeats. Sequences within this interval have been shown to assume a nuclease S1-hypersensitive structure in vitro. In this paper, we extend those in vitro observations, demonstrating that the S1-hypersensitive structure is triple-helical H-DNA formed by a symmetric (dC-dT).(dG-dA) sequence. Thus, the sequences that form H-DNA in vitro are also required in vivo for optimal hsp26 …

Distribution Patterns Of Hp1, A Heterochromatin-Associated Nonhistone Chromosomal Protein Of Drosophila, T James, J Eissenberg, C Craig, V Dietrich, A Hobson, Sarah C.R. Elgin

Biology Faculty Research

We have previously reported the identification of a nonhistone chromosomal protein (nhcp-19; now called HP1) preferentially associated with the heterochromatin of Drosophila melanogaster. A detailed study of the HP1 distribution pattern on polytene chromosomes by immunofluorescent staining, using monoclonal antibody C1A9, has been carried out. The results indicate that this protein is found within the centric beta-heterochromatin, in cytological regions 31, 41 and 80, and throughout polytene chromosome 4. Staining of telomeres is frequently observed, those of chromosome arms 2R and 3R and the X chromosome being the most conspicuous. Analysis of a fourth chromosome insertional translocation T(3;4)f/In(3L)P confirms an …

Drosophila Nuclear Proteins Bind To Regions Of Alternating C And T Residues In Gene Promoters, D Gilmour, G Thomas, Sarah C.R. Elgin

Biology Faculty Research

Proteins from Drosophila nuclei that bind to regions of alternating C and T residues present in the promoters of the heat shock genes hsp70 and hsp26 and the histone genes his3 and his4 have been purified. These proteins bind to isolated linear DNA, and genomic footprinting analyses indicate that they are bound to DNA in nuclei. In supercoiled plasmids at low pH, some of these DNA sequences adopt triple-helical structures which, if they form in vivo, could significantly affect chromatin structure. The nuclear proteins described here, and not necessarily the deformed conformation of the DNA, may be responsible for maintaining …

The Formation And Function Of Dnase I Hypersensitive Sites In The Process Of Gene Activation, Sarah C.R. Elgin

Biology Faculty Research

No abstract provided.

Drosophila Has A Single Copy Of The Gene Encoding A Highly Conserved Histone H2a Variant Of The H2a.F/Z Type, Angela Van Daal, E White, M Gorovsky, Sarah C.R. Elgin

Biology Faculty Research

The Tetrahymena histone H2A variant designated hv1 is localized exclusively in the transcriptionally active macronucleus and is absent from the quiescent micronucleus (1). A cDNA clone of the hv1 gene (2) was used to screen a Drosophila cDNA library. A cross-hybridizing clone was recovered and shown by sequence analysis to code for a protein homologous to hv1 as well as to the chicken H2A variant, H2A.F (3), the sea urchin H2A variant, H2A.F/Z (4) and the mammalian H2A variant H2A.Z (5). Southern analysis of Drosophila genomic DNA indicates that the H2AvD (H2A variant Drosophila) gene is present in one copy. …