The etiology and genetic alterations of follicular thyroid carcinoma are not well understood. By targeting a mutation (PV) into the thyroid hormone receptor beta gene (TRbetaPV mouse), we created a ...knock-in mutant TRbeta(PV/PV) mouse that spontaneously develop follicular thyroid carcinoma with progression to metastasis similar to human follicular thyroid carcinoma. This mouse model provides a valuable tool to ascertain the nature and the extent of genomic rearrangements that occur during carcinogenesis of the thyroid. Spectral karyotyping analysis (SKY) of seven cell lines derived from thyroid tumors developed in TRbeta(PV/PV) mice showed that all of them had abnormal karyotypes, with chromosome number ranging from near-diploid (39-42 chromosomes) to hypotetraploid (63-79 chromosomes). These seven cell lines also exhibited a variety of structural chromosomal aberrations, including common recurrent translocations and deletions. This SKY analysis shows that the development and progression of follicular thyroid carcinoma in knock-in TRbeta(PV/PV) mutant mice comprise recurrent structural and numerical genomic changes, some of which mimic those described in human thyroid cancer.
The etiology and genetic alterations of follicular thyroid carcinoma are not well understood. By targeting a mutation (PV) into the thyroid hormone receptor β gene (TRβPV mouse), we created a ...knock-in mutant TRβ
PV/PV mouse that spontaneously develop follicular thyroid carcinoma with progression to metastasis similar to human follicular thyroid carcinoma. This mouse model provides a valuable tool to ascertain the nature and the extent of genomic rearrangements that occur during carcinogenesis of the thyroid. Spectral karyotyping analysis (SKY) of seven cell lines derived from thyroid tumors developed in TRβ
PV/PV mice showed that all of them had abnormal karyotypes, with chromosome number ranging from near-diploid (39–42 chromosomes) to hypotetraploid (63–79 chromosomes). These seven cell lines also exhibited a variety of structural chromosomal aberrations, including common recurrent translocations and deletions. This SKY analysis shows that the development and progression of follicular thyroid carcinoma in knock-in TRβ
PV/PV mutant mice comprise recurrent structural and numerical genomic changes, some of which mimic those described in human thyroid cancer.
We revisited the cytogenetic alterations of the cervical adenocarcinoma cell line HeLa through the use of spectral karyotyping (SKY), comparative genomic hybridization (CGH), and fluorescence in situ ...hybridization (FISH). SKY analysis unequivocally characterized all abnormal chromosomes. Chromosomal breakpoints were primarily assigned by simultaneous assessment of SKY painted chromosomes and inverted 4,6-diamidino2-phenylindole banding from the same cell. Twenty clonally abnormal chromosomes were found. Comparison with previously reported HeLa G-banding karyotypes revealed a remarkably stable cytogenetic constitution because 18 of 20 markers that were found were present before. The classification of 12 markers was refined in this study. Our assignment of the remaining six markers was consistent with those described in the literature. The CGH map of chromosomal copy number gains and losses strikingly matched the SKY results and was, in a few instances, decisive for assigning breakpoints. The combined use of molecular cytogenetic methods SKY, CGH, and FISH with site-specific probes, in addition to inverted 4,6-diamidino-2-phenylindole or conventional G-banding analysis, provides the means to fully assess the genomic abnormalities in cancer cells. Human papillomaviruses (HPVs) are frequently integrated into the cellular DNA in cervical cancers. We mapped by FISH five HPV18 integration sites: three on normal chromosomes 8 at 8q24 and two on derivative chromosomes, der(5)t(5;22;8)(qll;q11q13;q24) and der(22)t(8; 22)(q24;q13), which have chromosome 8q24 material. An 8q24 copy number increase was detected by CGH. Dual-color FISH with a c-MYC probe mapping to 8q24 revealed colocalization with HPV18 at all integration sites, indicating that dispersion and amplification of the c-MYC gene sequences occurred after and was most likely triggered by the viral insertion at a single integration site. Numerical and structural chromosomal aberrations identified by SKY, genomic imbalances detected by CGH, as well as FISH localization of HPV18 integration at the c-MYC locus in HeLa cells are common and representative for advanced stage cervical cell carcinomas. The HeLa genome has been remarkably stable after years of continuous cultivation; therefore, the genetic alterations detected may have been present in the primary tumor and reflect events that are relevant to the development of cervical cancer.
Farber disease is an autosomal recessive disorder caused by lysosomal acid ceramidase (AC) deficiency. It commonly manifests during the first few months after birth with a unique triad of painful and ...progressive deformed joints, subcutaneous nodules, and progressive hoarseness. In order to understand the molecular mechanism(s) of pathogenesis of Farber disease, we isolated and characterized a full-length human AC gene, mapped its chromosomal location, determined the tissue-specific expression, and analyzed mutations in Farber disease patients. We also studied the AC-mRNA expression in gastrointestinal tumors and adjoining normal tissues. In addition, we determined the pattern of tissue-specific AC-mRNA expression in the adult mouse and during fetal development. Our results show that human AC gene consists of 14 exons and 13 introns spanning approximately 26.5 kb of genomic DNA. It is mapped to human chromosome 8p22–21.2, a region often disrupted in several cancers. The AC-mRNA is expressed in the mouse fetus from the seventh day of gestation. Interestingly, while the AC-mRNA is expressed in all segments of the normal gastrointestinal tract, none of the gastrointestinal tumor tissues had any AC-mRNA expression. We also uncovered four novel mutations in Farber disease patients that were not previously reported. Taken together, our results not only attest to the physiological importance of AC but also uncover several new mutations in Farber disease that may advance our knowledge towards establishing a genotype–phenotype correlation in this disease.
During anagen, cell proliferation in the germinative matrix of the hair follicle gives rise to the fiber and inner root sheath. The hair fiber is constructed from structural proteins belonging to ...four multigene families: keratin intermediate filaments, high-sulfur matrix proteins, ultra high-sulfur matrix proteins, and high glycine-tyrosine proteins. Several hair-specific keratin intermediate filament proteins have been characterized, and all have relatively cysteine-rich N- and C-terminal domains, a specialization that allows extensive disulfide cross-linking to matrix proteins. We have cloned two complete type II hair-specific keratin genes (ghHb1 and ghHb6). Both genes have nine exons and eight introns spanning about 7 kb and lying about 10 kb apart. The structure of both genes is highly conserved in the regions that encode the central rod domain but differs considerably in the C-terminal coding and noncoding sequences, although some conservation of introns does exist. These genes have been localized to the type II keratin cluster on chromosome 12q13 by fluorescence in situ hybridization. They, and their type I partner ghHa1, are expressed in differentiating hair cortical cells during anagen. In cultured follicles, ghHa1 expression declined in cortical cells and was no longer visible after 6 d, whereas the basal epidermal keratin hK14 appeared in the regressing matrix. The transition from anagen to telogen is marked by downregulation of hair cortical specific keratins and the appearance of hK14 in the epithelial sac to which the telogen hair fiber is anchored. Further studies of the regulation of these genes will improve our understanding of the cyclical molecular changes that occur as the hair follicle grows, regresses, and rests.
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