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M Rocchi

Publications and source records attributed to M Rocchi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Positive selection of a gene family during the emergence of humans and African apes.

Gene duplication followed by adaptive evolution is one of the primary forces for the emergence of new gene function. Here we describe the recent proliferation, transposition and selection of a 20-kilobase (kb) duplicated segment throughout 15 Mb of the short arm of human chromosome 16. The dispersal of this segment was accompanied by considerable variation in chromosomal-map location and copy number among hominoid species. In humans, we identified a gene family (morpheus) within the duplicated segment. Comparison of putative protein-encoding exons revealed the most extreme case of positive selection among hominoids. The major episode of enhanced amino-acid replacement occurred after the separation of human and great-ape lineages from the orangutan. Positive selection continued to alter amino-acid composition after the divergence of human and chimpanzee lineages. The rapidity and bias for amino-acid-altering nucleotide changes suggest adaptive evolution of the morpheus gene family during the emergence of humans and African apes. Moreover, some genes emerge and evolve very rapidly, generating copies that bear little similarity to their ancestral precursors. Consequently, a small fraction of human genes may not possess discernible orthologues within the genomes of model organisms.

Animals↗
PubMed2001

Characterization of a highly repeated DNA sequence family in five species of the genus Eulemur.

The karyotypes of Eulemur species exhibit a high degree of variation, as a consequence of the Robertsonian fusion and/or centromere fission. Centromeric and pericentromeric heterochromatin of eulemurs is constituted by highly repeated DNA sequences (including some telomeric TTAGGG repeats) which have so far been investigated and used for the study of the systematic relationships of the different species of the genus Eulemur. In our study, we have cloned a set of repetitive pericentromeric sequences of five Eulemur species: E. fulvus fulvus (EFU), E. mongoz (EMO), E. macaco (EMA), E. rubriventer (ERU), and E. coronatus (ECO). We have characterized these clones by sequence comparison and by comparative fluorescence in situ hybridization analysis in EMA and EFU. Our results showed a high degree of sequence similarity among Eulemur species, indicating a strong conservation, within the five species, of these pericentromeric highly repeated DNA sequences.

Animals↗
PubMed2001

Novel X-linked mental retardation syndrome with short stature maps to Xq24.

We describe a large family from Sardinia, Italy, in which a novel X- linked mental retardation (XLMR) syndrome segregates. The phenotype observed in the 8 affected males includes severe mental retardation (MR), lack of speech, coarse face, distinctive skeletal features with short stature, brachydactyly of fingers and toes, small downslanting palpebral fissures, large bulbous nose, hypoplastic ear lobe and macrostomia. Carrier females are not mentally retarded, although some of them have mild dysmorphic features such as minor ear lobe abnormalities, as well as language and learning problems. Linkage analysis for X-chromosome markers resulted in a maximum lod score of 3.61 with marker DXS1001 in Xq24. Recombination observed with flanking markers identified a region of 16 cM for further study. None of the other XLMR syndromes known to map in the same region shows the same composite phenotype. This evidence strongly suggests that the genetic disease in this family is unique.

Adolescent↗
PubMed2001

X/autosomal translocations in the Xq critical region associated with premature ovarian failure fall within and outside genes.

Premature ovarian failure curtails female reproductive life and is often linked to balanced Xq/autosomal translocations in a critical region. We mapped regions around translocations at the edges of this zone (one in Xq13.3, two in Xq26) in large-insert clones and analyzed their sequence. One Xq26 region is extensively transcribed and, in agreement with a recent independent analysis, the breakpoint interrupts a gene that encodes a widely expressed peptidase. In contrast 430 kb around the second Xq26 breakpoint has no putative or detected gene content. In 260 kb around the Xq13 translocation, the breakpoint falls among a cluster of repetitive elements at least 59 kb from the only detected gene (a rarely expressed T-box family transcription factor). We discuss our results in relation to models that ascribe premature ovarian failure to interruption of ovarian genes or to a failure of interactions involving DNA of the critical region during follicle development.

Chromosome Breakage↗
PubMed2001

Acute promyelocytic leukemia with additional chromosome abnormalities in a renal transplant case.

Some cases of acute myeloid leukemia following organ transplant (PT-AML) have been published in the literature. We report the second case of acute promyelocytic leukemia (APL), which developed post-transplant and immunosuppressive treatment, in a 50-year-old male who had undergone a renal transplant. At diagnosis he presented typical t(15;17)(q12;q13) with additional abnormalities, including +8,t(13;22)(q12;q13) and an abnormal chromosome 1 which was better characterized by fluorescence in situ hybridization (FISH). He obtained cytological, karyotypic and molecular complete remission (CR) with induction treatment according to the all-trans retinoic acid + idarubican (AIDA) protocol; after 12 months, he relapsed (molecular relapse) and achieved molecular remission with all-trans retinoic acid (ATRA) plus mitoxantrone and cytosine arabinoside. After a further 14 months, he was treated with arsenic trioxide for cytological relapse and obtained a third CR; at the cytological relapse the karyotype showed 47,XY,+8, t(15;17)(q22;q21),t(13;22)(q12;q13),der(22)t(1;22)(p22;q13). He is alive 3.3 years after diagnosis of APL. Cyclosporin A (CsA) was given during all cycles of chemotherapy. We did not observe any severe infections or kidney failure during treatments. The use of conventional cytogenetic analysis plus FISH may identify complex karyotype also in transplanted patients receiving immunotherapy, and may also contribute to a better assessment of PT-AL.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

A new multicolor-FISH approach for the characterization of marker chromosomes: centromere-specific multicolor-FISH (cenM-FISH).

Centromere-specific multi-color FISH (cenM-FISH) is a new multicolor FISH technique that allows the simultaneous characterization of all human centromeres by using labeled centromeric satellite DNA as probes. This approach allows the rapid identification of all human centromeres by their individual pseudo-coloring in one single step and is therefore a powerful tool in molecular cytogenetics. CenM-FISH fills a gap in multicolor karyotyping using WCP probes and distinguishes all centromeric regions apart from the evolutionary highly conserved regions on the chromosomes 13 and 21. The usefulness of the cenM-FISH technique for the characterization of small supernumerary marker chromosomes with no (or nearly no) euchromatin and restricted amounts of available sample material is demonstrated in prenatal, postnatal, and tumor cytogenetic cases. In addition, rarely described markers with the involvement of heterochromatic material inserted into homogeneously staining regions could be identified and characterized by using the cenM-FISH technique.

Centromere↗
PubMed2001

The structure of duplications on human acrocentric chromosome short arms derived by the analysis of 15p.

We report the molecular analysis of a 130-kb DNA region containing a junction between beta and non-beta satellite DNA from chromosome 15p. The genomic region is characterized by beta satellite blocks intermingled with variants of the D4Z4 repeat, and duplicons from 4q24 and 4q35. Besides the p-arm of acrocentric chromosomes, the duplicons showed a wide genomespread involving pericentromeric, sub-telomeric, and interstitial regions. In this regard, the paralogous sequences were characterized by a high similarity index (96%), thus indicating a recent transposition during the evolution. The acrocentrics differedwith regard to the location of the 4q24 paralogous region, since it mapped on the p-arm of chromosomes 13-15 and 21, but only on 22q11.2. Conversely, the 4q35 duplication marked the p-arm of all the acrocentrics. In different individuals, the short arm of acrocentric chromosomes revealed a great variability of sequence representation and location at p11 and/or p13 for both the 4q24 and 4q35 duplications. The studied genomic region from chromosome 15p, of which a contig of approximately 200 kb has been derived, could lead to more detailed investigations into the sequence organization and possible biological function of chromosome regions that are located close to the rDNA array.

Alu Elements↗
PubMed2001

AcroM fluorescent in situ hybridization analyses of marker chromosomes.

The presence of a de novo supernumerary marker chromosome (SMC) poses problems in genetic counseling. The consequences of the additional chromosomal material may range from harmless to detrimental. As the composition of a SMC cannot be deciphered by traditional banding analysis, sophisticated methods are needed for their rapid and detailed analyses. A new strategy is presented, which allows the elucidation of the composition of SMCs in one or two hybridizations. One hybridization, termed AcroM-FISH, involves a newly generated probe mix, which consists of painting probes for all acrocentric chromosomes, centromere probes for chromosomes 13/21, 14/22, 15, and a probe specific for rDNA, each labeled with a specific combination of fluorochromes. This probe mix is sufficient to characterize approximately 80% of all SMCs. For the other 20% of SMCs, chromosomes can be analyzed in a second hybridization by multicolor karyotyping, for example, multiplex FISH (M-FISH), to check for the presence of euchromatin of other chromosomes. The potential of AcroM-FISH was tested in various applications.

Adult↗
PubMed2001

A novel translocation t(2;9)(q14;p12) in AML-M2 with an uncommon phenotype: myeloperoxidase-positive and myeloid antigen-negative.

We report a case of acute myeloid leukemia (AML-M2) expressing myeloperoxidase (MPO) but no myeloid antigens. A few cases with this discordant phenotype have been reported and an association has been suggested between the lack of CD13 and CD33 in MPO positive AML and the presence of t(8;21). Cytogenetic and molecular analyses performed in our case showed 48,XY,+Y,+8,t(2;9)(q14;p12). We believe that combined approaches can contribute to detect particular AL cases like the present one, that confirms the heterogeneity of AML. However, further studies are needed to clarify the relationship between phenotypic aberrations and cytogenetic abnormalities.

Adult↗
PubMed2001

The putative forkhead transcription factor FOXL2 is mutated in blepharophimosis/ptosis/epicanthus inversus syndrome.

In type I blepharophimosis/ptosis/epicanthus inversus syndrome (BPES), eyelid abnormalities are associated with ovarian failure. Type II BPES shows only the eyelid defects, but both types map to chromosome 3q23. We have positionally cloned a novel, putative winged helix/forkhead transcription factor gene, FOXL2, that is mutated to produce truncated proteins in type I families and larger proteins in type II. Consistent with an involvement in those tissues, FOXL2 is selectively expressed in the mesenchyme of developing mouse eyelids and in adult ovarian follicles; in adult humans, it appears predominantly in the ovary. FOXL2 represents a candidate gene for the polled/intersex syndrome XX sex-reversal goat.

Abnormalities, Multiple↗
PubMed2001

Saturating density of STSs (1/6 kb) in a 1.1 Mb region on 3q28-q29: a valuable resource for cloning of disease genes.

We have fine mapped 29 ESTs of Genemap'99 to YACs and radiation hybrids covering 8 cM of the chromosomal region of 3q28-q29. Focusing on the genetic interval of approximately 1 Mb between markers D3S3669 and D3S3562 we established a sequence-ready PAC contig which covers the OPA1 locus containing the gene causing autosomal dominant optic atrophy (ADOA; OMIM*165500). The fidelity of the contig was increased by the generation of 181 PAC end sequences, 84 of which resulted in PCR-able STSs. Sequence content evaluation of the PAC ends by BLAST analysis identified two novel ESTs localising to the OPA1 crucial interval.

Chromosome Mapping↗
PubMed2001

Centromere emergence in evolution.

Evolutionary centromere repositioning is a paradox we have recently discovered while studying the conservation of the phylogenetic chromosome IX in primates. Two explanations were proposed: a conservative hypothesis assuming sequential pericentric inversions, and a more challenging assumption involving centromere emergence during evolution. The complex evolutionary history showed by chromosome IX did not allow us to clearly distinguish between these two hypotheses. Here we report comparative studies of chromosome X in two lemur species: the black lemur and the ringtailed lemur. The X chromosome is telocentric in the black lemur and almost metacentric in the ringtailed lemur. The marker order along these chromosomes, however, was found to be perfectly colinear with humans. Our data unequivocally point to centromere emergence as the most likely explanation of centromere repositioning.

Animals↗
PubMed2001

Assignment to chromosome 12q24.33, gene organization and splicing of the human KRAB/FPB containing zinc finger gene ZNF84.

FISH analysis was used to assign the human ZNF84 gene to chromosome 12q24.33, a region associated with recurrent breakpoints and allelic loss in several human cancers. In this report we show that the ZNF84 coding region is organized in four exons; two are dedicated to encoding the KRAB/FPB-A and KRAB/FPB-B modules, the remaining exons encode the N-terminal amino acids and C-terminal array of zinc finger units, respectively.

Amino Acid Sequence↗
PubMed2001

Genomic organization and mapping of the gene (SLC25A19) encoding the human mitochondrial deoxynucleotide carrier (DNC).

The deoxynucleotide carrier (DNC) transports deoxynucleotides into mitochondria and is therefore essential for mtDNA synthesis. The human DNC gene (SLC25A19) spans about 16.5 kb and consists of nine exons with the translation start site in exon 4. It is located on chromosome 17q25.3. Three transcripts, which differ in their 5' ends and are generated by alternative splicing, have been identified.

Alternative Splicing↗
PubMed2001

Reconstruction of the female Gorilla gorilla karyotype using 25-color FISH and multicolor banding (MCB).

The origin of the human and great ape chromosomes has been studied by comparative chromosome banding analysis and, more recently, by fluorescence in situ hybridization (FISH), using human whole-chromosome painting probes. It is not always possible, however, to determine the exact breakpoints and distribution or orientation of specific DNA regions using these techniques. To overcome this problem, the recently developed multicolor banding (MCB) probe set for all human chromosomes was applied in the present study to reanalyze the chromosomes of Gorilla gorilla (GGO). While the results agree with those of most previous banding and FISH studies, the breakpoints for the pericentric inversion on GGO 3 were defined more precisely. Moreover, no paracentric inversion was found on GGO 14, and no pericentric inversions could be demonstrated on GGO 16 or 17.

Animals↗
PubMed2001

[Importance of dermatologic screening within the frame work of a general cancer prevention program].

BACKGROUND: Skin tumours represent about 11% of all the malignant neoplasms and their frequency is increasing annually. Skin tumours (melanoma, basal and squamous cell carcinoma, etc.) can be used for a good screening activity, but in relation to breast or cervix uteri cancer needs to be better defined. A test on a population of selected patients against skin malignant neoplasms has been carried out in our Centre. All of them had skin lesions and further checks were necessary. METHODS: The diagnostic protocol used in our Centre for Oncological Prevention uses the collection of anamnestic data and an objective examination. Between 1996 and 2000, 222 patients between the ages of 18 and 80 have been selected. All of them had suspected skin lesions. The patients were selected by the oncologist, particularly for pigmentation, asymmetry, irregular borders and heterogeneous colour of their skin lesions. Subsequently, the patients were sent for a further examination to the dermatologist oncologist, who on the basis of the objective dermatological examination with possible dermatoscopy, made a clinical diagnosis of the skin injuries or suggested surgical removal for the histological control of the same. RESULTS: Requested consultations: 222. Exami-nations made: 195. Patients considered: 190. Skin injuries examined: 190. The following skin lesions were identified: melanoma: 4 (2.1%) [2: I Clark level; 2: II Clark level]; basal cell carcinoma: 14 (7.37%); dermatofibrosarcoma: 1 (0.53%); keratoacanthoma: 1 (0.53%); dysplastic nevus: 4 (2.1%); actinic keratosis: 7 (3.68%); benign lesions: 159 (83.68%). CONCLUSIONS: These data were obtained by a screening program and it is therefore not a random study. This study shows interesting results because tumoral skin lesions and in particular melanoma were recognised at early stages. This is more than enough for us to create a specific screening program for skin lesions to cut down the rate of morbidity and mortality.

Adult↗
PubMed2001

[The significance of "atypical metaplasia" in the follow-up of patients operated for bladder cancer].

BACKGROUND: The aim of this study was to evaluate the clinical usefulness of urinary cytology in the follow-up of patients who under-went surgery for bladder cancer. Particularly, the positive predictive value of urinary cytology and time elapsed between a positive test and the diagnosis of a cystoscopically confirmed bladder tumor are analyzed. METHODS: This study was carried out at the Cytological Laboratory Department of Experimental Medicine and Pathology, University La Sapienza, Rome. Among 230 cases studied since 1996, 30 male patients over 50 were examined (25 with a previous bladder cancer and 5 with a previous prostate cancer) with long time follow-up, who underwent more than two cytological examinations on voided urine (2-12) at pre-fixed intervals. RESULTS: Nine (30%) of the patients suffered from recurrent disease. The cytological examinations was positive in 8 out of the 9 positive cases and negative in 17 out of the 21 negative cases. Absence of disease was confirmed in all the latter cases both by cystoscopic examination and clinical follow-up. One negative case showed clearly malignant cells in more than one specimen taken at different time intervals. This patient is actually under strict control. In 5 cases atypical metaplasia was present in the cytological specimen. In two of those cases cystoscopic examination 5 and 8 months later confirmed progressive disease. In the other three cases cystoscopy showed no evidence of disease. Two of the patients are well and alive after 2 and 14 months respectively. One is dead of prostatic cancer. CONCLUSIONS: Considering the cases of atypical metaplasi as positive the cytological examinations showed 100% sensibility, 81% specificity, a predictive negative value of 1 and a predictive positive value of 0.66.

Follow-Up Studies↗