Defining the beginning and end of KpnI family segments.

Grimaldi, Giovanna; Skowroński, Jacek; Singer, Maxine

doi:10.1002/j.1460-2075.1984.tb02042.x

Cited by 198 publications

(146 citation statements)

References 27 publications

(29 reference statements)

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“…Hybridization to the genomic DNAs followed a uniform distribution (Fig. 5B), also previously observed by others (13), confirming that differences in transcript distribution were not due to the distribution of different regions of genomic L1Hs 5ЈUTR.…”

Section: Resultssupporting

confidence: 87%

Antisense Promoter of Human L1 Retrotransposon Drives Transcription of Adjacent Cellular Genes

Speek

2001

Molecular and Cellular Biology

377

350

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In the human genome, retrotranspositionally competent long interspersed nuclear elements (L1Hs) are involved in the generation of processed pseudogenes and mobilization of unrelated sequences into existing genes. Transcription of each L1Hs is initiated from its internal promoter but may also be driven from the promoters of adjacent cellular genes. Here I show that a hitherto unknown L1Hs antisense promoter (ASP) drives the transcription of adjacent genes. The ASP is located in the L1Hs 5 untranslated region (5 UTR) and works in the opposite direction. Fifteen cDNAs, isolated from a human NTera2D1 cDNA library by a differential screening method, contained L1Hs 5 UTRs spliced to the sequences of known genes or non-proteincoding sequences. Four of these chimeric transcripts, selected for detailed analysis, were detected in total RNA of different cell lines. Their abundance accounted for roughly 1 to 500% of the transcripts of four known genes, suggesting a large variation in the efficiency of L1Hs ASP-driven transcription. ASP-directed transcription was also revealed from expressed sequence tag sequences and confirmed by using an RNA dot blot analysis. Nine of the 15 randomly selected genomic L1Hs 5 UTRs had ASP activities about 7-to 50-fold higher than background in transient transfection assays. ASP was assigned to the L1Hs 5 UTR between nucleotides 400 to 600 by deletion and mutation analysis. These results indicate that many L1Hs contain active ASPs which are capable of interfering with normal gene expression, and this type of transcriptional control may be widespread.

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Section: Resultssupporting

confidence: 87%

Antisense Promoter of Human L1 Retrotransposon Drives Transcription of Adjacent Cellular Genes

Speek

2001

Molecular and Cellular Biology

377

350

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“…ORFeus insertions are expected to be even more stable than native L1 insertions because the ORFeus sequence is sufficiently divergent from endogenous mouse L1s to prevent homologous recombination between the two. Finally, unlike DNA transposons, L1 insertions are frequently 5Ј truncated (2,(4)(5)(6)(7), although the mechanism of truncation is unknown (30,63). Our data indicate that Ϸ25% of ORFeus insertions are Ͻ502 bp long (Table 4), which places a restriction on the cargo size for L1 transgenes and demands the design of L1 vectors with compact reporter elements such as epitope tags.…”

Section: Discussionmentioning

confidence: 87%

“…The human genome contains Ͼ500,000 L1 copies, most of which are 5Ј truncated (2,(4)(5)(6)(7). Full-length L1s are Ϸ6 kb in length, containing an internal promoter in the 5Ј UTR, two nonoverlapping ORFs (ORF1 and ORF2) and a 3Ј UTR followed by a poly(A) tail (8)(9)(10)(11).…”

mentioning

confidence: 99%

Active retrotransposition by a synthetic L1 element in mice

Han

Wheelan

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

105

146

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Long interspersed element type 1 (L1) retrotransposons are ubiquitous mammalian mobile elements and potential tools for in vivo mutagenesis; however, native L1 elements are relatively inactive in mice when introduced as transgenes. We have previously described a synthetic L1 element, ORFeus, containing two synonymously recoded ORFs relative to mouse L1. It is significantly more active for retrotransposition in cell culture than all native L1 elements tested. To study its activity in vivo, we developed a transgenic mouse model in which ORFeus expression was controlled by a constitutive heterologous promoter, and we established definitive evidence for ORFeus retrotransposition activity both in germ line and somatic tissues. Germ line retrotransposition frequencies resulting in 0.33 insertions per animal are seen among progeny of ORFeus donor element heterozygotes derived from a single founder, representing a >20-fold increase over native L1 elements. We observe somatic transposition events in 100% of the ORFeus donor-containing animals, and an average of 17 different insertions are easily recovered from each animal; modeling suggests that the number of somatic insertions per animal exceeds this number by perhaps several orders of magnitude. Nearly 200 insertions were precisely mapped, and their distribution in the mouse genome appears random relative to transcription units and guanine-cytosine content. The results suggest that ORFeus may be developed into useful tools for in vivo mutagenesis.gene trap ͉ integration site preference ͉ LINE-1 ͉ retrotransposon ͉ transgenic mouse

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“…The problem of myc activation and its transcriptional level was recently studied extensively in mouse plasmacytomas and Burkitt lymphoma. In these studies it was not always easy to find the normal cellular counterpart to the transformed cell such that the comparison was meaningful (40,41). This problem is even more significant in TVT because little is known about the cell type of this tumor.…”

Section: Methodsmentioning

confidence: 99%

"Retroposon" insertion into the cellular oncogene c-myc in canine transmissible venereal tumor.

Katzir¹,

Rechavi²,

Cohen³

et al. 1985

Proc. Natl. Acad. Sci. U.S.A.

112

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We examined by Southern blotting the state of the cellular oncogene c-myc In the dog transmissible venereal tumor. The tumor DNA contains a 16.8-kilobase pair (kbp) rearranged c-myc fragment in addition to the normal 15-kbp and 7.5-kbp fragments. We compared the structure of the cloned rearranged c-myc (rc-myc) with that of a cloned normal c-myc and found that the rearrangement was due to the insertion of a 1.8-kbp DNA upstream to the first exon of c-myc. The inserted DNA is flanked by 10-base-pair direct repeats and contains a dA-rich tail, suggesting its origin from mRNA. Partial sequence of the inserted element showed 62% homology with the primate interdispersed Kpn I repetitive element. These results provide an example for the behavior of repetitive DNA sequences like the Kpn I family, as movable elements that can transpose nearby to oncogenes or other structural genes and perhaps affect their activity.

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Defining the beginning and end of KpnI family segments.

Cited by 198 publications

References 27 publications

Antisense Promoter of Human L1 Retrotransposon Drives Transcription of Adjacent Cellular Genes

Antisense Promoter of Human L1 Retrotransposon Drives Transcription of Adjacent Cellular Genes

Active retrotransposition by a synthetic L1 element in mice

"Retroposon" insertion into the cellular oncogene c-myc in canine transmissible venereal tumor.

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