scholarly journals Site-selected insertion of the transposon Tc1 into a Caenorhabditis elegans myosin light chain gene.

1993 ◽  
Vol 13 (2) ◽  
pp. 902-910 ◽  
Author(s):  
A M Rushforth ◽  
B Saari ◽  
P Anderson
Keyword(s):  
Polymerase Chain Reaction ◽  
Caenorhabditis Elegans ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Null Alleles ◽  
Chain Gene ◽  
Splice Sites ◽  
Chain Reaction ◽  
Light Chain Gene ◽  
Polymerase Chain

We used the polymerase chain reaction to detect insertions of the transposon Tc1 into mlc-2, one of two Caenorhabditis elegans regulatory myosin light chain genes. Our goals were to develop a general method to identify mutations in any sequenced gene and to establish the phenotype of mlc-2 loss-of-function mutants. The sensitivity of the polymerase chain reaction allowed us to identify nematode populations containing rare Tc1 insertions into mcl-2. mlc-2::Tc1 mutants were subsequently isolated from these populations by a sib selection procedure. We isolated three mutants with Tc1 insertions within the mlc-2 third exon and a fourth strain with Tc1 inserted in nearby noncoding DNA. To demonstrate the generality of our procedure, we isolated two additional mutants with Tc1 insertions within hlh-1, the C. elegans MyoD homolog. All of these mutants are essentially wild type when homozygous. Despite the fact that certain of these mutants have Tc1 inserted within exons of the target gene, these mutations may not be true null alleles. All three of the mlc-2 mutants contain mlc-2 mRNA in which all or part of Tc1 is spliced from the pre-mRNA, leaving small in-frame insertions or deletions in the mature message. There is a remarkable plasticity in the sites used to splice Tc1 from these mlc-2 pre-mRNAs; certain splice sites used in the mutants are very different from typical eukaryotic splice sites.

Site-selected insertion of the transposon Tc1 into a Caenorhabditis elegans myosin light chain gene

1993 ◽  
Vol 13 (2) ◽  
pp. 902-910
Author(s):  
A M Rushforth ◽  
B Saari ◽  
P Anderson
Keyword(s):  
Polymerase Chain Reaction ◽  
Caenorhabditis Elegans ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Null Alleles ◽  
Chain Gene ◽  
Splice Sites ◽  
Chain Reaction ◽  
Light Chain Gene ◽  
Polymerase Chain

We used the polymerase chain reaction to detect insertions of the transposon Tc1 into mlc-2, one of two Caenorhabditis elegans regulatory myosin light chain genes. Our goals were to develop a general method to identify mutations in any sequenced gene and to establish the phenotype of mlc-2 loss-of-function mutants. The sensitivity of the polymerase chain reaction allowed us to identify nematode populations containing rare Tc1 insertions into mcl-2. mlc-2::Tc1 mutants were subsequently isolated from these populations by a sib selection procedure. We isolated three mutants with Tc1 insertions within the mlc-2 third exon and a fourth strain with Tc1 inserted in nearby noncoding DNA. To demonstrate the generality of our procedure, we isolated two additional mutants with Tc1 insertions within hlh-1, the C. elegans MyoD homolog. All of these mutants are essentially wild type when homozygous. Despite the fact that certain of these mutants have Tc1 inserted within exons of the target gene, these mutations may not be true null alleles. All three of the mlc-2 mutants contain mlc-2 mRNA in which all or part of Tc1 is spliced from the pre-mRNA, leaving small in-frame insertions or deletions in the mature message. There is a remarkable plasticity in the sites used to splice Tc1 from these mlc-2 pre-mRNAs; certain splice sites used in the mutants are very different from typical eukaryotic splice sites.

Myosin light-chain 1 and 3 gene has two structurally distinct and differentially regulated promoters evolving at different rates

1985 ◽  
Vol 5 (11) ◽  
pp. 3168-3182
Author(s):  
E E Strehler ◽  
M Periasamy ◽  
M A Strehler-Page ◽  
B Nadal-Ginard
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Mammalian Species ◽  
In Vitro Transcription ◽  
Chain Gene ◽  
Promoter Regions ◽  
Light Chain Gene ◽  
Direct Initiation

DNA fragments located 10 kilobases apart in the genome and containing, respectively, the first myosin light chain 1 (MLC1f) and the first myosin light chain 3 (MLC3f) specific exon of the rat myosin light chain 1 and 3 gene, together with several hundred base pairs of upstream flanking sequences, have been shown in runoff in vitro transcription assays to direct initiation of transcription at the cap sites of MLC1f and MLC3f mRNAs used in vivo. These results establish the presence of two separate, functional promoters within that gene. A comparison of the nucleotide sequence of the rat MLC1f/3f gene with the corresponding sequences from mouse and chicken shows that: the MLC1f promoter regions have been highly conserved up to position -150 from the cap site while the MLC3f promoter regions display a very poor degree of homology and even the absence or poor conservation of typical eucaryotic promoter elements such as TATA and CAT boxes; the exon/intron structure of this gene has been completely conserved in the three species; and corresponding exons, except for the regions encoding most of the 5' and 3' untranslated sequences, show greater than 75% homology while corresponding introns are similar in size but considerably divergent in sequence. The above findings indicate that the overall structure of the MLC1f/3f genes has been maintained between avian and mammalian species and that these genes contain two functional and widely spaced promoters. The fact that the structures of the alkali light chain gene from Drosophila melanogaster and of other related genes of the troponin C supergene family resemble a MLC3f gene without an upstream promoter and first exon strongly suggests that the present-day MLC1f/3f genes of higher vertebrates arose from a primordial alkali light chain gene through the addition of a far-upstream MLC1f-specific promoter and first exon. The two promoters have evolved at different rates, with the MLC1f promoter being more conserved than the MLC3f promoter. This discrepant evolutionary rate might reflect different mechanisms of promoter activation for the transcription of MLC1f and MLC3f RNA.

Promoter upstream elements of the chicken cardiac myosin light-chain 2-A gene interact with trans-acting regulatory factors for muscle-specific transcription

1989 ◽  
Vol 9 (6) ◽  
pp. 2513-2525
Author(s):  
T Braun ◽  
E Tannich ◽  
G Buschhausen-Denker ◽  
H H Arnold
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Mutational Analysis ◽  
Nuclear Proteins ◽  
Chain Gene ◽  
Cardiac Myosin ◽  
Mobility Shift ◽  
Light Chain Gene ◽  
Sequence Elements

A segment of the 5'-flanking region of the chicken cardiac myosin light-chain gene extending from nucleotide -64 to the RNA start site is sufficient to allow muscle-specific transcription. In this paper, we characterize, by mutational analysis, sequence elements which are essential for the promoter activity. Furthermore, we present evidence for a negative-acting element which is possibly involved in conferring the muscle specificity. Nuclear proteins specifically bind to the DNA elements, as demonstrated by gel mobility shift assays and DNase I protection footprinting. The significance of the DNA-protein interactions for the function of the promoter in vivo is demonstrated by competition experiments in which protein-binding oligonucleotides were microinjected into nuclei of myotubes, where they successfully competed for the protein factors which are required to trans activate the MLC2-A promoter. The ability to bind nuclear proteins involves two closely spaced AT-rich sequence elements, one of which constitutes the TATA box. The binding properties correlate well with the capacity to activate transcription in vivo, since mutations in this region of the promoter concomitantly lead to loss of binding and transcriptional activity.

Mutations in the 8 kDa dynein light chain gene disrupt sensory axon projections in the Drosophila imaginal CNS

Development ◽  
1996 ◽  
Vol 122 (10) ◽  
pp. 2955-2963 ◽  
Author(s):  
R. Phillis ◽  
D. Statton ◽  
P. Caruccio ◽  
R.K. Murphey
Keyword(s):  
Light Chain ◽  
Cytoplasmic Dynein ◽  
Null Alleles ◽  
Chain Gene ◽  
Sensory Axon ◽  
Axon Pathfinding ◽  
Dynein Light Chain ◽  
Light Chain Gene ◽  
Point Of Entry ◽  
Mutant Female

Mutations in an 8 kDa (8x10(3) Mr) cytoplasmic dynein light chain disrupt sensory axon trajectories in the imaginal nervous system of Drosophila. Weak alleles are behaviorally mutant, female-sterile and exhibit bristle thinning and bristle loss. Null alleles are lethal in late pupal stages and alter neuronal anatomy within the imaginal CNS. We utilized P[Gal4] inserts to examine the axon projections of stretch receptor neurons and an engrailed-lacZ construct to characterize the anatomy of tactile neurons. In mutant animals both types of sensory neurons exhibited altered axon trajectories within the CNS, suggesting a defect in axon pathfinding. However, the alterations in axon trajectory did not prevent these axons from reaching their normal termination regions. In the alleles producing these neuronal phenotypes, expression of the cytoplasmic dynein 8 kDa light chain gene is completely absent. These results demonstrate a new function for the cytoplasmic dynein light chain in the regulation of axonogenesis and may provide a point of entry for studies of the role of cellular motors in growth cone guidance.

Can Polymerase Chain Reaction Help Distinguish Benign From Malignant Lymphoid Aggregates in Bone Marrow Aspirates?

2000 ◽  
Vol 124 (4) ◽  
pp. 511-515
Author(s):  
Jonathan Ben-Ezra ◽  
Kirk Hazelgrove ◽  
Andrea Ferreira-Gonzalez ◽  
Carleton T. Garrett
Keyword(s):  
Bone Marrow ◽  
Polymerase Chain Reaction ◽  
Heavy Chain ◽  
Immunoglobulin Heavy Chain ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Immunoglobulin Heavy Chain Gene ◽  
Chain Reaction ◽  
Polymerase Chain ◽  
Lymphoid Aggregates

Abstract Objective.—Although morphologic and immunologic clues are helpful in distinguishing benign from malignant lymphoid aggregates in bone marrow biopsies, there remain some cases in which it is not possible to arrive at a definitive diagnosis. Since the malignant aggregates are monoclonal B-cell proliferations, we sought to determine whether performing polymerase chain reaction for the immunoglobulin heavy-chain locus would be helpful in distinguishing these 2 entities. Methods and Results.—Scrapings from unstained bone marrow aspirate smears or touch preparations of bone marrow biopsies from 15 patients with benign bone marrow lymphoid aggregates and 18 patients with malignant lymphoid infiltrates were analyzed for rearrangements of the FR3 region of the immunoglobulin heavy-chain gene locus by a heminested polymerase chain reaction procedure. All specimens had amplifiable DNA, as shown by amplification of the ras proto-oncogene. None of the 15 cases of benign bone marrow lymphoid aggregates demonstrated clonality upon amplification of the immunoglobulin heavy-chain gene locus. In contrast, 8 of the 18 malignant samples were positive (P = .01 by χ2 test; sensitivity, 44%; specificity, 100%; positive predictive value, 100%; negative predictive value, 60%). There was a tendency for there to be more lymphocytes in stained bone marrow aspirate smears from the cases of malignant lymphoid aggregates with a positive polymerase chain reaction result than in those without demonstrable clonality (36.0 ± 35.4% vs 9.8 ± 8.0%, P = .13). Conclusions.—Polymerase chain reaction for the immunoglobulin heavy-chain gene locus may help distinguish benign from malignant bone marrow lymphoid aggregates. Although the presence of false-negative samples may be related to the relative lack of lymphocytes in the bone marrow aspirates, other factors, such as the lack of amplification of the FR3 region of the immunoglobulin heavy-chain gene locus in particular tumors, cannot be ruled out with certainty.

scholarly journals Nodular lymphocyte-predominant Hodgkin's disease associated with large- cell lymphoma: analysis of Ig gene rearrangements by V-J polymerase chain reaction

Blood ◽  
1996 ◽  
Vol 88 (2) ◽  
pp. 657-666 ◽  
Author(s):  
TC Greiner ◽  
RD Gascoyne ◽  
ME Anderson ◽  
DW Kingma ◽  
SA Adomat ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
B Cell ◽  
Hodgkin's Disease ◽  
Hodgkin’S Disease ◽  
Large Cell ◽  
Single Step ◽  
Chain Gene ◽  
Gene Rearrangements ◽  
Chain Reaction ◽  
Polymerase Chain

The clonality of nodular lymphocyte-predominant Hodgkin's disease (NLPHD) and the relationship to composite or sequential large-cell lymphomas (LCLs) is poorly understood. Clonal Ig heavy-chain gene rearrangements (lgHGR) have infrequently been observed in NLPHD by Southern hybridization. The goals of this study were (1) to determine if IgHGR could be identified by polymerase chain reaction (PCR) techniques in the LCL associated with NLPHD; (2) to determine if the lgHGR identified in the LCL could also be found in the associated NLPHD; and (3) to determine if Epstein-Barr virus (EBV) played a role a role in histologic progression to LCL. Using consensus primers to conserved regions in the lgH variable (V) and joining (J) region genes, we analyzed formalin-fixed paraffin-embedded sections from the biopsies of 25 patients referred to the National Cancer Institute (NCI) registry for NLPHD and LCL using both single-step and seminested V-J PCR. The histologically aggressive component was further subclassified as frank LCL or as L&H-cell-rich, but not fulfilling criteria for LCL. Matched samples representing both NLPHD and aggressive components were available in 13 cases. In 12 cases, only one component was available (aggressive, n = 8; NLPHD, n = 4). In addition, we also amplified, with 32P labeling, 12 cases of NLPHD without associated LCL. Two clonal IgHGR were identified in 29 cases (7%) of typical NLPHD, both of which were associated with LCL containing a similar sized band by PCR. The clonal identity of the bands in the NLPHD and associated LCL was confirmed by sequencing the products in these two cases. Eight of 10 cases (80%) of LCL associated with NLPHD contained a clonal band by this technique. By contrast, none of the cases classified as L&H-cell- rich contained an IgHGR. The single-step and seminested PCR methods produced identical results. All clonal LCLs were studied for EBV sequences by in situ hybridization using the EBER1 probe, and were negative. We conclude that the LCLs associated with NLPHD are clonal B- cell malignancies. However, by these methods, the same clone can be identified in only a minority of cases of NLPHD and LCL. EBV does not appear to play a role in histologic progression. Moreover, our results suggest that many cases suspected of being LCL may actually represent NLPHD with increased numbers of L&H cells. In histologically equivocal cases, the diagnosis of LCL should be reserved for those cases in which a clonal B-cell neoplasm can be demonstrated.

Myosin Light Chain Gene Expression Associated with Disease States of the Human Heart

1993 ◽  
Vol 25 (5) ◽  
pp. 577-585 ◽  
Author(s):  
T. Trahair ◽  
T. Yeoh ◽  
T. Cartmill ◽  
A. Keogh ◽  
P. Spratt ◽  
...  
Keyword(s):  
Gene Expression ◽  
Light Chain ◽  
Human Heart ◽  
Myosin Light Chain ◽  
Chain Gene ◽  
Light Chain Gene ◽  
Disease States
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