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J Bullerdiek

Publications and source records attributed to J Bullerdiek.

At least 19 recordsLinked to original sources
PubMed2006

[Research into the human genome driven by improved methods].

The enormous progress made by research of the human genome is mainly driven by newly established or improved methods for the analysis of nucleic acids and proteins. Among the methods that have gained a wide-spread use within a comparably short time are fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR) including methods for quantitative PCR, and the use of short interfering RNA (siRNA) molecules aimed at gene silencing. The increasing significance of the analysis of secondary modifications of nucleic acids and proteins (genomic imprinting by DNA methylation, posttranslational protein modification) is reflected by an increasing use of mass spectrometry for the analysis and characterization of these biomolecules. Overall, in the future the research into the human genome and the interpretation of data will further benefit from these and other refined tools.

Animals↗
PubMed2006

Evidence for a 3p25 breakpoint hot spot region in thyroid tumors of follicular origin.

Epithelial tumors of the thyroid are cytogenetically well-investigated tumors. So far, the main cytogenetic subgroups, characterized by trisomy 7 and by rearrangements of either 19q13 or 2p21, respectively, have been described. Recently, we have been able to describe the involvement of a novel gene called THADA in benign thyroid lesions with 2p21 rearrangements. Other fusion genes found in thyroid lesions are RET/PTC and PAX8/PPAR(gamma). The latter occurs in follicular thyroid carcinomas with a t(2;3)(q13;p25). Here we present molecular-cytogenetic and cytogenetic investigations on a follicular thyroid adenoma with a t(2;20;3)(p21;q11.2; p25). In this case, an intronic sequence of PPAR(gamma) is fused to exon 28 of THADA. We used BAC clones containing the genomic sequence of PPARgamma for fluorescence in situ hybridization to confirm the localization of the breakpoint within intron 2 of PPAR(gamma) . Our findings suggest that the close surrounding of PPAR(gamma) is a breakpoint hot spot region, leading to recurrent alterations of this gene in thyroid tumors of follicular origin including carcinomas as well as adenomas with or without involvement of PAX8.

Adenocarcinoma, Follicular↗
PubMed2005

RAS gene hot-spot mutations in canine neoplasias.

Point mutations in the cellular homologues HRAS, KRAS2, and NRAS of the viral Harvey and Kirsten rat sarcoma virus oncogenes are commonly involved in the onset of malignancies in humans and other species such as dog, mouse, and rat. Most often, three particular hot-spot codons are affected, with one amino acid exchange being sufficient for the induction of tumor growth. While RAS genes have been shown to play an important role in canine tumors such as non-small lung cell carcinomas, data about RAS mutations in canine fibrosarcomas as well as KRAS2 mutations in canine melanomas is sparse. To increase the number of tumors examined, we recently screened 13 canine fibrosarcomas and 11 canine melanomas for point mutations, particularly within the mutational hot spots. The results were compared to the already existing data from other studies about these tumors in dogs.

Animals↗
PubMed2005

Establishment of a cell line derived from a canine prostate carcinoma with a highly rearranged karyotype.

Akin to the situation in humans, dogs are frequently affected by tumors of the prostate. The malignancies share many similarities between both species, for example, median age at the onset of the disease and metastatic behavior. In human prostatic tumor samples, investigations of prepared metaphase spreads showed a variety of chromosomal aberrations, with trisomies of chromosomes 7, 8, and 17 as the leading cytogenetic abnormalities. In this article we present one case of a canine adenocarcinoma of the prostate, including clinical examination and establishment of a cell line from a tumor sample obtained from the affected 10-year-old male Briard. Searching for similarities between both species in respect to chromosomal changes within the tumor samples, we investigated prepared metaphases of the canine cell line cytogenetically. These investigations presented a highly rearranged karyotype showing a large biarmed marker consisting of material from chromosomes 1 and 2 in addition to centromeric fusions between dog chromosomes 1 and 5 that both could be identified in every metaphase investigated, while centric fusions of chromosomes 4 and 5 occurred in up to 50% of the metaphases. The cell line grew very well and showed evidence of being spontaneously immortalized when it crossed the 20th passage.

Adenocarcinoma↗
PubMed2005

"Best friends" sharing the HMGA1 gene: comparison of the human and canine HMGA1 to orthologous other species.

HMGA1 nonhistone proteins are reported to participate in various cellular processes including regulation of inducible gene transcription, integration of retroviruses into chromosomes, and the induction of neoplastic transformation and promotion of metastatic progression of cancer cells. Overexpression of HMGA1 was shown to be characteristic for various malignant tumors, suggesting a relation between the neoplastic phenotype and a high titer of the protein. Also chromosomal aberrations affecting the human HMGA1 gene at 6p21 were described in several tumors, e.g., uterine leiomyomas, pulmonary chondroid hamartomas, and follicular thyroid adenomas. We characterize the molecular structure of the canine HMGA1 cDNA, its splice variants, and predicted proteins HMGA1a and HMGA1b. Furthermore, we compared the CDS of both splice variants for 12 different breeds, screened them for SNPs, characterised a basic expression pattern, and mapped the gene via FISH. Additionally, we compared the known human, canine, murine, rat, hamster, bovine, pig, Xenopus, and chicken HMGA1 transcripts.

Animals↗
PubMed2005

[Significance of molecular-cytogenetic findings in mucoepidermoid carcinoma as an example of salivary gland tumors].

Chromosome translocations in tumors frequently give rise to fusion genes encoding proteins with oncogenic activities. Mucoepidermoid carcinomas (MEC) are characterized by a t(11;19)(q21-22;p13) translocation found in approximately 60% of the tumors. This t(11;19) translocation results in a fusion gene consisting of exon 1 of the MECT 1 gene and exons 2-5 of the MAML 2 gene. As a result of the t(11;19) a fusion protein is generated which, independent of NOTCH-ligands, activates the transcription of the NOTCH target gene HES 1. The altered function of MAML 2 causes a disruption of NOTCH signalling which suggests a novel mechanism of tumorigenesis. Pending the elucidation of the t(11;19) at the molecular level of an apparently identical chromosomal translocation in Warthin's tumor, the identification of the translocation in MEC by FISH- and/or RT-PCR-analyses may become important in diagnosis and might have prognostic relevance. Warthin's tumors are benign salivary gland neoplasms with a distinctive histomorphology and histogenesis completely different from MEC.

Carcinoma, Mucoepidermoid↗
PubMed2003

Human HMGA2 promoter is coregulated by a polymorphic dinucleotide (TC)-repeat.

HMGA proteins are thought to be causally involved in the progression of different diseases, including benign and malignant tumors, obesity, arteriosclerosis, and restenosis. As HMGA proteins are architectural transcription factors, their binding to DNA leads to changes in DNA-conformation modulating the environment for the assembly and function of transcriptional complexes, thus influencing the expression of a huge variety of genes. Despite the emerging role of HMGA proteins for important diseases, only limited information is available about mechanisms regulating the expression of the HMGA2 gene. In this report, 2240 bp of the 5' flanking region of the HMGA2 gene were functionally analyzed by luciferase assay experiments. Besides the identification of novel positive and negative regulatory elements, it was shown that transcription is initiated from two independent promoter regions within cell lines HeLa, MCF7, and L14TSV40. Furthermore, a functional polymorphic dinucleotide repeat (TCTCT(TC)(n)) 500 bp upstream of the ATG translational start codon was found to regulate strongly the human HMGA2 promoter with an activation pattern that correlates to its TC-repeat length.

Dinucleotide Repeats↗
PubMed2003

Molecular characterization of the canine HMGB1.

Due to the close similarities of numerous canine diseases to their human counterparts, the dog could join the mouse as the species of choice to unravel the genetic background of complex diseases as e.g. cancer and metabolic diseases. Accordingly, the role of the dog as a model for therapeutic approaches is strongly increasing. However, prerequisite for such studies is the characterization of the corresponding canine genes. Recently, the human high mobility group protein B1 (HMGB1) has attracted considerable interest of oncologists because of what is called its "double life". Besides its function as an architectural transcription factor HMGB1 can also be secreted by certain cells and then acts as a ligand for the receptor for advanced glycation end products (RAGE). The binding of HMGB1 to RAGE can activate key cell signaling pathways, such as p38(MAPK), JNK, and p42/p44(MAPK) emphasizing the important role of HMGB1 in inflammation and tumor metastasis. These results make HMGB1 a very interesting target for therapeutic studies done in model organisms like the dog. In this study we characterized the molecular structure of the canine HMGB1 gene on genomic and cDNA levels, its predicted protein, the gene locus and a basic expression pattern.

Amino Acid Sequence↗
PubMed2003

A 3.4-kbp transcript of ZNF331 is solely expressed in follicular thyroid adenomas.

Translocations involving chromosomal region 19q13 are a frequent finding in follicular adenomas of the thyroid and might represent the most frequent type of structural aberration in human epithelial tumors. By positional cloning, a putative candidate gene, ZNF331 (formerly RITA) located close to the breakpoint was identified. Recently, aberrant expression of ZNF331 has been described in two cell lines of follicular thyroid adenomas with aberrations in 19q13 indicating an involvement of ZNF331 in tumorigenesis. Nevertheless, knowledge about structure and expression of ZNF331 is limited. We performed RACE-PCR and genomic sequence analyses to gain a deeper insight into its molecular structure. To elucidate ZNF331 expression patterns we performed Northern blot analyses on various normal tissues as well as on thyroid carcinoma and adenoma cell lines. Herein, unique expression of a 3.4-kbp transcript is described in thyroid adenoma cell lines with 19q13 aberrations, which was not detected either in normal tissues or in thyroid carcinoma cell lines.

Adenoma↗
PubMed2003

High mobility group protein HMGA1 expression in breast cancer reveals a positive correlation with tumour grade.

Members of the HMGA protein (high mobility group protein A) family act as master switches of the chromatin structure by bending DNA and thus modulating the formation of transcription factor complexes of a number of target genes. Accordingly, HMGA proteins have been shown to be associated with the development and/or progression of a variety of benign and malignant tumours. Nevertheless, the HMGA1 expression studies published so far have not included primary breast cancer samples. In this study we have investigated the HMGA1 expression patterns in a series of 170 breast cancer samples by immunohistochemistry. We have found a strong variation in HMGA1 expression between the tumours. Based on an immunoreactive score (IRS) 14.1% of the tumour samples were scored to IRS 8-12 (strong positivity for HMGA1), 24.7% were scored to IRS 4-6 (moderate positivity), 25.3% were scored to IRS 1-3 (weak positivity), and 35.9% showed no positivity at all. Immunoreaction could be detected in all histological types of breast cancers analysed with the exception of invasive papillary and cribriform carcinoma. Statistical analysis revealed a strong correlation between tumour grade and HMGA1 expression (rs=0.3516, p<0.0001). Thus, the HMGA1 expression level can be considered a potential prognostic marker for breast cancer.

Breast Neoplasms↗
PubMed2001

Significant correlation between the breakpoints of rare clonal aberrations in benign solid tumors and the assignment of HMGIY retropseudogenes.

Recently, we described a mechanism by which a retropseudogene, during evolution, becomes an exon of a pre-existing active gene. Similar mechanisms may account for the activation of processed genes by chromosomal rearrangements in neoplasms. Because genes of the high-mobility group protein family HMGI(Y) are known to be involved in the development of a variety of benign solid tumors, it was the aim of the present study to analyze breakpoints of clonal chromosome abnormalities in that group of benign tumors for a possible correlation with retropseudogenes of the HMGIY gene. Whereas the HMGIYL1 retrospeudogene has recently been mapped to Xp22.1, we assigned a further retropseudogene by FISH to 4q13, and database research allowed us to assign a third retropseudogene to 12q24.1. Sequence analyses of these retropseudogenes revealed high-identity indices to the HMGIY gene and no frame-shift divergences. Breakpoint information was obtained from cytogenetic aberrations in uterine leiomyomas, lipomas, pleomorphic adenomas, and pulmonary chondroid hamartomas because, in all of these tumor entities, cytogenetic subgroups involving genes of the HMGI(Y) family exist. Chromosomal bands harboring HMGIY retropseudogenes were affected with a significantly higher frequency than expected under the assumption of purely randomly occurring breakages. These results support our hypothesis that HMGIY-related retropseudogenes can be affected by chromosomal rearrangements in benign human tumors.

Base Sequence↗