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Papers by Robert Gemmill

This dataset contains the digitized treatments in Plazi based on the original journal article Cie... more This dataset contains the digitized treatments in Plazi based on the original journal article Ciegler, Janet C., Gemmill, Robert M. (2018): Additional state records for Coleoptera of South Carolina. Insecta Mundi 636: 1-5, DOI: http://doi.org/10.5281/zenodo.3708130

Genetics, 1985

A cloned ä-amylase cDNA sequence from the mouse is homologous to a small set of DNA sequences fro... more A cloned ä-amylase cDNA sequence from the mouse is homologous to a small set of DNA sequences from Drosophila melanogaster under appropriate conditions of hybridization. A number of recombinant lambda phage that carry homologous Drosophila genomic DNA sequences were isolated using the mouse clone as a hybridization probe. Putative amylase clones hybridized in situ to one or the other of two distinct sites in polytene chromosome 2R and were assigned to one of two classes, A and B. Clone λDm32, representing class A, hybridizes within chromosome section 53CD. Clone λDm65 of class B hybridizes within section 54A1-B1. Clone λDm65 is homologous to a 1450- to 1500-nucleotide RNA species, which is sufficiently long to code for α-amylase. No RNA homologous to λDm32 was detected. We suggest that the class B clone, λDm65, contains the functional Amy structural gene(s) and that class A clones contain an amylase pseudogene.

Journal of Bacteriology, 1984

Two mutations that affect expression of the Salmonella typhimurium leu operon were investigated. ... more Two mutations that affect expression of the Salmonella typhimurium leu operon were investigated. leu operon DNA from these mutant strains was cloned, and nucleotide sequences of the leu control regions were determined. leu-500, which eliminates expression of all four leu genes simultaneously, is a point mutation in the-10 region of the leu promoter. leu-2012 is a point mutation within the-35 region of the leu promoter. leu-2012 suppressed leucine auxotrophy caused by leu-500 only when the medium contained a carbon source that does not cause catabolite repression. A cya mutation (adenylate cyclase deficiency) introduced into the leu-500 leu-2012 strain caused leu enzymes to be made only if cAMP was supplied exogenously. A leu-500 leu-2012 strain containing a crp mutation (cAMP receptor protein deficiency), on the other hand, could not make leu enzymes even in the presence of cAMP. In vitro transcription experiments demonstrated that the leu-2012 mutation created a new transcription initiation site. RNA polymerase utilized this site in vitro in the absence of added cAMP receptor protein and cAMP.

Science signaling, Jan 17, 2017

Neuropilins (NRP1 and NRP2) are co-receptors for heparin-binding growth factors and class 3 semap... more Neuropilins (NRP1 and NRP2) are co-receptors for heparin-binding growth factors and class 3 semaphorins. Different isoforms of NRP1 and NRP2 are produced by alternative splicing. We found that in non-small cell lung cancer (NSCLC) cell lines, transforming growth factor-β (TGFβ) signaling preferentially increased the abundance of NRP2b. NRP2b and NRP2a differ only in their carboxyl-terminal regions. Although the presence of NRP2b inhibited cultured cell proliferation and primary tumor growth, NRP2b enhanced cellular migration, invasion into Matrigel, and tumorsphere formation in cultured cells in response to TGFβ signaling and promoted metastasis in xenograft mouse models. These effects of overexpressed NRP2b contrast with the effects of overexpressed NRP2a. Hepatocyte growth factor (HGF)-induced phosphorylation of the kinase AKT was specifically promoted by NRP2b, whereas inhibiting the HGF receptor MET attenuated NRP2b-dependent cell migration. Unlike NRP2a, NRP2b did not bind the ...

PLOS ONE, 2016

Epithelial-mesenchymal transition (EMT) is one mechanism of acquired resistance to inhibitors of ... more Epithelial-mesenchymal transition (EMT) is one mechanism of acquired resistance to inhibitors of the epidermal growth factor receptor-tyrosine kinases (EGFR-TKIs) in non-small cell lung cancer (NSCLC). The precise mechanisms of EMT-related acquired resistance to EGFR-TKIs in NSCLC remain unclear. We generated erlotinib-resistant HCC4006 cells (HCC4006ER) by chronic exposure of EGFR-mutant HCC4006 cells to increasing concentrations of erlotinib. HCC4006ER cells acquired an EMT phenotype and activation of the TGF-β/SMAD pathway, while lacking both T790M secondary EGFR mutation and MET gene amplification. We employed gene expression microarrays in HCC4006 and HCC4006ER cells to better understand the mechanism of acquired EGFR-TKI resistance with EMT. At the mRNA level, ZEB1 (TCF8), a known regulator of EMT, was >20-fold higher in HCC4006ER cells than in HCC4006 cells, and increased ZEB1 protein level was also detected. Furthermore, numerous ZEB1 responsive genes, such as CDH1 (E-cadherin), ST14, and vimentin, were coordinately regulated along with increased ZEB1 in HCC4006ER cells. We also identified ZEB1 overexpression and an EMT phenotype in several NSCLC cells and human NSCLC samples with acquired EGFR-TKI resistance. Shortinterfering RNA against ZEB1 reversed the EMT phenotype and, importantly, restored erlotinib sensitivity in HCC4006ER cells. The level of micro-RNA-200c, which can negatively regulate ZEB1, was significantly reduced in HCC4006ER cells. Our results suggest that increased ZEB1 can drive EMT-related acquired resistance to EGFR-TKIs in NSCLC. Attempts should be made to explore targeting ZEB1 to resensitize TKI-resistant tumors.

Frontiers in Biological Detection: From Nanosensors to Systems V, 2013

Detection of biomolecules on microarrays based on label-free on-chip optical biosensors is very a... more Detection of biomolecules on microarrays based on label-free on-chip optical biosensors is very attractive since this format avoids complex chemistries caused by steric hindrance of labels. Application areas include the detection of cancers and allergens, and food-borne pathogens to name a few. We have demonstrated photonic crystal microcavity biosensors with high sensitivity down to 1pM concentrations (67pg/ml). High sensitivities were achieved by slow light engineering which reduced the radiation loss and increased the stored energy in the photonic crystal microcavity resonance mode. Resonances with high quality factor Q~26,760 in liquid ambient, coupled with larger optical mode volumes allowed enhanced interaction with the analyte biomolecules which resulted in sensitivities down to 10 cells per micro-liter to lung cancer cell lysates. The specificity of detection was ensured by multiplexed detections from multiple photonic crystal microcavities arrayed on the arms of a multimode interference power splitter. Specific binding interactions and control experiments were performed simultaneously at the same instant of time with the same 60 microliter sample volume. Specificity is further ensured by sandwich assay methods in the multiplexed experiment. Sandwich assay based amplification increased the sensitivity further resulting in the detection of lung cancer cell lysates down to concentrations of 2 cells per micro-liter. The miniaturization enabled by photonic crystal biosensors coupled with waveguide interconnected layout thus offers the potential of high throughput proteomics with high sensitivity and specificity.

IEEE Photonics Conference 2012, 2012

We experimentally detect lung cancer cell lysates with high sensitivity down to 2 cells per micro... more We experimentally detect lung cancer cell lysates with high sensitivity down to 2 cells per microliter with silicon based photonic crystal microcavity sensors. Label free specificity is achieved via sandwiched assays and simultaneous multiplexed detection.

Clinical cancer research : an official journal of the American Association for Cancer Research, 2000

Lung carcinogenesis is assumed to be a multistep process, but detailed understanding of the seque... more Lung carcinogenesis is assumed to be a multistep process, but detailed understanding of the sequential morphological and molecular changes preceding invasive lung cancer remains elusive. To better understand early lung carcinogenesis, we initiated a program of fluorescence bronchoscopy in smokers at high risk for lung cancer. In the bronchial biopsies from these subjects, we observed a unique lesion consisting of capillary blood vessels closely juxtaposed to and projecting into metaplastic or dysplastic squamous bronchial epithelium, angiogenic squamous dysplasia (ASD). Serial sections of the capillary projections confirmed that they represent intramucosal capillary loops. Microvessel density in ASD was elevated in comparison to normal mucosa (P = 0.0003) but not in comparison to other forms of hyperplasia or dysplasia. ASD thus represents a qualitatively distinct form of angiogenesis in which there is architectural rearrangement of the capillary microvasculature. Genetic analysis o...

Cancer research, Jan 15, 1998

Hemizygous deletion in the short (p) arm of chromosome 3 is a common finding in non-small cell lu... more Hemizygous deletion in the short (p) arm of chromosome 3 is a common finding in non-small cell lung carcinoma (NSCLC) and is postulated to be a crucial early change in lung tumorigenesis. Yet one of the most frequent nuclear abnormalities in both NSCLC and premalignant bronchial epithelium is increase in chromosomal copy number. Deletion and duplication have not been assessed in the same tumor set by both molecular and cytogenetic methods to determine whether allelic loss correlates with chromosomal duplication in the same tumor cell populations. It is also not established what biological mechanisms might lead to allelic deletion and chromosomal duplication. We have investigated changes in the copy number of chromosome 3 in touch preparations of 38 NSCLCs (19 adenocarcinomas and 19 squamous cell carcinomas) using dual-target, dual-color fluorescence in situ hybridization (FISH) assays. Chromosome 3 centromere probe was matched with a 3p14.2 probe [intron 4 of the fragile histidine t...

Cancer research, 1997

Cytogenetic and molecular studies have implied the presence of tumor suppressor genes (TSGs) on c... more Cytogenetic and molecular studies have implied the presence of tumor suppressor genes (TSGs) on chromosome 9p that are critical in the development of lung and other cancers. The p16/CDKN2 gene, a cyclin dependent kinase inhibitor, is a well-defined TSG on 9p21. Although the frequency of mutations in the p16/CDKN2 gene has been detected in approximately 30% of non-small cell lung cancer, loss of heterozygosity on 9p has been observed in greater than 70% of non-small cell lung cancers. These and other deletion mapping studies have suggested the existence of additional TSGs on 9p. This study examined chromosome 9p for TSG loci by analyzing 23 squamous cell carcinomas of the lung with 21 microsatellite markers. Loss of heterozygosity was detected in all of the tumors, and homozygous deletions of the p16/ CDKN2 locus were observed in 6 of the 23 tumors (26%). In addition, a novel region of homozygous deletion was detected in six tumors (26%) at D9S126, approximately 2.5 cM proximal to p1...

Cancers, 2013

The epithelial to mesenchymal transition (EMT) enables epithelial cells with a migratory mesenchy... more The epithelial to mesenchymal transition (EMT) enables epithelial cells with a migratory mesenchymal phenotype. It is activated in cancer cells and is involved in invasion, metastasis and stem-like properties. ZEB1, an E-box binding transcription factor, is a major suppressor of epithelial genes in lung cancer. In the present study, we show that in H358 non-small cell lung cancer cells, ZEB1 downregulates EpCAM (coding for an epithelial cell adhesion molecule), ESRP1 (epithelial splicing regulatory protein), ST14 (a membrane associated serine protease involved in HGF processing) and RAB25 (a small G-protein) by direct binding to these genes. Following ZEB1 induction, acetylation of histone H4 and histone H3 on lysine 9 (H3K9) and 27 (H3K27) was

Proceedings of the National Academy of Sciences, 2003

E-cadherin loss in cancer is associated with de-differentiation, invasion, and metastasis. Drosop... more E-cadherin loss in cancer is associated with de-differentiation, invasion, and metastasis. Drosophila DE-cadherin is regulated by Wnt/β-catenin signaling, although this has not been demonstrated in mammalian cells. We previously reported that expression of WNT7a, encoded on 3p25, was frequently downregulated in lung cancer, and that loss of E-cadherin or β-catenin was a poor prognostic feature. Here we show that WNT7a both activates E-cadherin expression via a β-catenin specific mechanism in lung cancer cells and is involved in a positive feedback loop. Li + , a GSK3β inhibitor, led to E-cadherin induction in an inositol-independent manner. Similarly, exposure to mWNT7a specifically induced free β-catenin and E-cadherin. Among known transcriptional suppressors of E-cadherin, ZEB1 was uniquely correlated with E-cadherin loss in lung cancer cell lines, and its inhibition by RNA interference resulted in E-cadherin induction. Pharmacologic reversal of E-cadherin and WNT7a losses was ach...

Proceedings of the National Academy of Sciences, 1979

The nucleotide sequence of the control region of the leu operon of Salmonella typhimurium was det... more The nucleotide sequence of the control region of the leu operon of Salmonella typhimurium was determined. A prominent feature of this region is a signal for termination of transcription. In vitro, transcription does terminate at this site, yielding a leader RNA of about 160 nucleotides as a major product. This leader RNA is potentially translatable into a peptide containing 28 amino acids, 4 of which are adjacent leucine residues. Several regions of base complementarity exist within the leader, positioned such that pairing of one region precludes pairing of another. The position of the four leucine codons relative to two regions of base complementarity suggest a model for the regulation of the leu operon similar to that proposed by Yanofsky and coworkers for the trp operon. In addition, a third region of base complementarity was identified which, when incorporated into the model, explains why premature termination is the usual outcome when transcription is initiated in vitro by puri...

Oncogene, 2002

VHL is part of an SCF related E3-ubiquitin ligase complex with`gatekeeper' function in renal carc... more VHL is part of an SCF related E3-ubiquitin ligase complex with`gatekeeper' function in renal carcinoma. However, no mutations have been identi®ed in VHL interacting proteins in wild type VHL tumors. We previously reported that the TRC8 gene was interrupted by a t(3;8) translocation in a family with hereditary renal and non-medullary thyroid cancer. TRC8 encodes a multi-membrane spanning protein containing a RING-H2 ®nger with in vitro ubiquitin ligase activity. We isolated the Drosophila homologue, DTrc8, and studied its function by genetic manipulations and a yeast 2-hybrid screen. Human and Drosophila TRC8 proteins localize to the endoplasmic reticulum. Loss of either DTrc8 or DVhl resulted in an identical ventral midline defect. Direct interaction between DTrc8 and DVhl was con®rmed by GST-pulldown and co-immunoprecipitation experiments. CSN-5/JAB1 is a component of the COP9 signalosome, recently shown to regulate SCF function. We found that DTrc8 physically interacts with CSN-5 and that human JAB1 localization is dependent on VHL mutant status. Lastly, overexpression of DTrc8 inhibited growth consistent with its presumed role as a tumor suppressor gene. Thus, VHL, TRC8, and JAB1 appear to be linked both physically and functionally and all three may participate in the development of kidney cancer.

Oncogene, 2006

TRC8/RNF139 and von Hippel-Lindau (VHL) both encode E3 ubiquitin (Ub) ligases mutated in clear-ce... more TRC8/RNF139 and von Hippel-Lindau (VHL) both encode E3 ubiquitin (Ub) ligases mutated in clear-cell renal carcinomas (ccRCC). VHL, inactivated in nearly 70% of ccRCCs, is a tumor suppressor encoding the targeting subunit for a Ub ligase complex that downregulates hypoxia-inducible factor-a. TRC8/RNF139 is a putative tumor suppressor containing a sterol-sensing domain and a RING-H2 motif essential for Ub ligase activity. Here we report that human kidney cells are growth inhibited by TRC8. Inhibition is manifested by G2/M arrest, decreased DNA synthesis and increased apoptosis and is dependent upon the Ub ligase activity of the RING domain. Tumor formation in a nude mouse model is inhibited by TRC8 in a RING-dependent manner. Expression of TRC8 represses genes involved in cholesterol and fatty acid biosynthesis that are transcriptionally regulated by the sterol response element binding proteins (SREBPs). Expression of activated SREBP-1a partially restores the growth of TRC8-inhibited cells. These data suggest that TRC8 modulation of SREBP activity comprises a novel regulatory link between growth control and the cholesterol/lipid homeostasis pathway.

Oncogene, 2005

TRC8 encodes an E3-ubiquitin ligase disrupted in a family with hereditary renal cell carcinoma (R... more TRC8 encodes an E3-ubiquitin ligase disrupted in a family with hereditary renal cell carcinoma (RCC). We previously reported that Drosophila Trc8 (DTrc8) overexpression inhibits growth and that human and fly proteins interact with with the COP9 signalosome (CSN) subunit JAB1/CSN5. However, further mechanistic evidence linking DTrc8 growth suppression to CSN5 was lacking. Here, we show that haploinsufficiency of CSN5, or a T100I point mutation (CSN5 3), relieved growth suppression by DTrc8, whereas CSN5 1 (E160V) and CSN5 2 (G147D) mutations had no effect. The strength of yeast two-hybrid interactions between DTrc8 and CSN5 were in complete agreement with the observed phenotypes. DTrc8 overexpression resulted in elevated levels of CSN5 and CSN7, but had no effect on NEDD8-modified Cul-1. In contrast to CSN5, heterozygosity for CSN4 null had no effect on the DTrc8 phenotype. We also looked for genetic interactions between DTrc8 and other MPN domain proteins in the CSN and 26S proteasome lid. CSN6 haploinsufficiency restored growth, whereas reduction of proteasome subunits RPN8 or RPN11 had no effect. DTrc8 expression increased the level of digitonin-extractable CSN complex, consistent with elevated levels of CSN5 and 7. Our genetic results confirm that DTrc8induced growth suppression is CSN5 (and CSN6) dependent. While there was no obvious influence on CSN deneddylation activity, the increase in CSN subunits and holocomplex suggests that TRC8 modulates signalosome levels or compartmentalization.

Molecular Cancer, 2009

The tumor suppressor gene TRC8/RNF139 is disrupted by a constitutional balanced translocation t(8... more The tumor suppressor gene TRC8/RNF139 is disrupted by a constitutional balanced translocation t(8;22)(q24.13;q11.21) in a young girl with dysgerminoma

Lung Cancer, 1997

likely site for one or more tumor suppressor genes critical to lung tumor development. Analysis o... more likely site for one or more tumor suppressor genes critical to lung tumor development. Analysis of 13 polymorphic loci permitted Hibi et a!. (18) to propose three separate and apparently independent targets for LOH in lung tumors within bands 3p2S, 3p2l.3, and 3cen-pl4. Although Hibi et a!. (18) did not find any 3p homozygous deletions, such changes have proven highly useful for defining specific small targets likely to harbor tumor suppressor genes in other tumor types such as melanoma (19). Recurrent homozygous deletions have been reported in three SCLC cell lines within 3p2l.3 (20â€"23) whereas one SCLC line [U2020 (24)] contains a deletion within 3pi2â€"i3. We have recently shown that 3p2l.3 harbors two independent sites of homozygous deletion and observed deletions in the distal region (3p2l.33) in uncultured tumors of both SCLC and non-SCLC histology (25). In addition, we and others have observed recurrent homozygous dde tions in 3pl4.2 in carcinoma cell lines of diverse origin (26â€"28). These sites coincide approximately with regions identified by Hibi et al. (18), although this is likely due to the large size of the areas identified in this early study. Similar sites have been shown to undergo LOH in carcinomas of the kidney (29â€"31),cervix (32, 33), head and neck (34), and nasopharynx (35). Data supporting tumor suppressor function have come from chromosome and DNA transfer studies suggesting that both the 3p2l.3 region and a more proximal site including 3pl2â€"l4 can suppress tumorigenicity of cancer cell lines in athymic nude mice (36, 37). Although a number of candidate genes have been identified within some deletions [FHJT (27); GNAI2 (38), semaphorin P1(25), SEMA5 (39), ITGA4L (40)], none have been confirmed to act as tumor suppressors. To clarify the role of 3p in lung tumorigenesis and to more precisely identify targets for positional cloning efforts, we have utilized a series of 32 highly polymorphic microsatellite loci (41â€"44) to examine lung tumors for genetic deletions. Most of these loci have known genetic and physical map positions (42, 45, 46) and known orders, resulting in relatively unambiguous inter pretations. Small cell (SCLC) tumors included 33 cell lines and 26 matched tumor/normal SCLC biopsy samples. Two non-SCLC tumors were also obtained from one of these SCLC patients. Non-SCLC tumors included 12 cell lines and 23 matched tumor/ normal biopsy samples with squamous histology. The results con firmed the high rates of 3p deletion in both SCLC and non-SCLC. One homozygous deletion was detected in a non-SCLC cell line within 3pl4.2, although this region was never found homozy gously deleted in uncultured tumors. Importantly, we identified one SCLC tumor with a homozygous deletion in 3pl2. Three squamous carcinomas were identified with homozygous deletions in 3p2l.31, coincident with the semaphorin IV and GNAJ2 genes. These results demonstrate that homozygous deletions occur in at least a subset of uncultured tumors. Our results also show that deletions within 3p2l.3l are not restricted to SCLC cell lines and can occur in non-SCLC tumors with squamous histology. These data indicate that 3p involvement in lung cancer is complex with multiple deletion targets and the potential for independent, cumu lative, or synergistic effects on lung tumor development.

Journal of Thoracic Oncology, 2009

Background: We investigated the incidence of eukaryotic translation initiation factor 3 subunit H... more Background: We investigated the incidence of eukaryotic translation initiation factor 3 subunit H (EIF3H) and MYC amplification in non-small cell lung cancer (NSCLC) patients, and whether MYC/ EIF3H increased gene copy number affected response to Epidermal Growth Factor Receptor tyrosine kinase inhibitors. Methods: Metastatic NSCLC patients (n ϭ 54) treated with gefitinib were analyzed for the genomic content of EIF3H and MYC genes by fluorescence in situ hybridization (FISH) using a customdesigned 3-color DNA probe set. Result: Amplification of EIF3H (ratio EIF3H/CEP8 Ͼ2), was observed in 10 cases (18.5%), and MYC was coamplified in all. MYC amplification without coamplification of EIF3H was observed in 2 cases (3.7%). Receiver operating characteristic analysis was conducted to identify the cutoff for MYC and EIF3H copy number best discriminating sensitive and resistant populations. MYC FISH positive patients (MYCϩ, mean Ն2.8) had a significantly higher response rate (p ϭ 0.003), longer time to progression (p ϭ 0.01) and overall survival (OS: p ϭ 0.02) than MYCϪ (mean Ͻ2.8). Similarly, EIF3H FISH positive patients (EIF3Hϩ, mean Ն2.75) had a significantly higher response rate (p ϭ 0.002), longer time to progression (p ϭ 0.01) and OS (p ϭ 0.01) than EIF3HϪ (mean Ͻ2.75). Conclusion: Our results indicate that MYC and EIF3H are frequently coamplified in NSCLC and that a high copy number correlates with increased epidermal growth factor receptor tyrosine kinase inhibitors sensitivity.