Organization and expression of 5S rRNA genes in the parasitic nematode,<i>Brugia malayi</i>

Ransohoff, Richard M.; Denker, John A.; Takacs, Adrienne M.; Hannon, Gregory J.; Nilsen, Timothy W.

doi:10.1093/nar/17.10.3773

Cited by 12 publications

(3 citation statements)

References 25 publications

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“…19 We found very little intraspecific variation in the spacer region in M. streptocerca, but sufficient interspecific differences to design species-specific primers.…”

Section: Resultsmentioning

confidence: 73%

“…Since the organization of the 5S rRNA gene was studied in detail in the filaria B. malayi, 19 and since DNA sequence information is also available from many other filarial species of different genera, 11,20 similar assays could be easily developed to classify larvae of other filaria species. Such PCR assays could be used to identify larvae in vectors or to identify zoonotic filarial infections in humans.…”

Section: Resultsmentioning

confidence: 99%

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Detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction-based assay.

Fischer

Büttner²,

Bamuhiiga³

et al. 1998

Am J Trop Med Hyg

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Abstract. To differentiate the skin-dwelling filariae Mansonella streptocerca and Onchocerca volvulus, a nested polymerase chain reaction (PCR) assay was developed from small amounts of parasite material present in skin biopsies. One nonspecific and one specific pair of primers were used to amplify the 5S rDNA spacer region of M. streptocerca. Biopsies with different microfilaria densities obtained from 104 Ugandans living in an area endemic for M. streptocerca were tested using both the nested PCR assay and standard parasitologic assessment of microfilariae. All 82 samples from microfilaria carriers were positive when tested using the nested PCR assay. In addition, M. streptocerca DNA could be detected in 16 samples thought to be microfilaria negative. Furthermore, six days following ivermectin treatment, M. streptocerca DNA was found in 12 of 14 microfilaria-negative biopsies. Control skin samples from patients infected with O. volvulus were all negative in the nested PCR assay. This assay improves the diagnosis of M. streptocerca and will facilitate further epidemiologic studies.When evaluating skin disease cases in large regions of Africa, the two skin-dwelling filarial species, Mansonella streptocerca and Onchocerca volvulus, must be considered as possible causative agents. Mansonella streptocerca infection is characterized by acute and more often chronic papular dermatitis mainly on the upper part of the body, which make it difficult to differentiate streptocerciasis and onchocerciasis clinically. 1, 2 In addition, after treatment with diethylcabarmazine or ivermectin, persons infected with M. streptocerca also show a typical Mazzotti reaction. 1, 3 Cross-reactions between O. volvulus and Mansonella species impede the differentiation of these parasites by serologic diagnosis using worm extracts. 4 Although isolated microfilariae (mf) of both species can be differentiated morphologically, species differentiation in histologic sections is difficult. Since the mf densities of M. streptocerca are often relatively low, methods other than the standard skin snip technique are required for accurate detection of this species. Collagenase digestion of the skin snips is an appropriate procedure, 2 but if a patient is also heavily infected with O. volvulus it may be difficult to detect one M. streptocerca mf among hundreds of O. volvulus mf. In these cases, a specific but more sensitive assay to detect M. streptocerca is clearly required.The polymerase chain reaction (PCR) is a sensitive technique to detect parasite DNA. Sensitive and specific PCR assays have been developed for the diagnosis of the human filarial parasites Wuchereria bancrofti, Brugia malayi, Loa loa, and O. volvulus. 5-10 All of these assays are based on different repetitive target sequences found only within a distinct filarial genus. In the present study, we have developed a PCR assay based on a target sequence present in all filarial and all other nematode species. 11 The 5S rDNA spacer region was amplified from DNA prepared from human skin biopsi...

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“…19 We found very little intraspecific variation in the spacer region in M. streptocerca, but sufficient interspecific differences to design species-specific primers.…”

Section: Resultsmentioning

confidence: 73%

Section: Resultsmentioning

confidence: 99%

Detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction-based assay.

Fischer

Büttner²,

Bamuhiiga³

et al. 1998

Am J Trop Med Hyg

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“…In typical human cells, there are ∼400 copies of a 43-kb rRNA gene unit arranged in tandem repeats with a head-to-tail orientation on the five acrocentric chromosomes ( 10 , 11 ). Each rRNA gene unit can be divided into two major parts: coding region and non-coding intergenic spacer (IGS) region.…”

Section: Introductionmentioning

confidence: 99%

Folate deficiency facilitates recruitment of upstream binding factor to hot spots of DNA double-strand breaks of rRNA genes and promotes its transcription

Xie

Song

et al. 2016

Nucleic Acids Research

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The biogenesis of ribosomes in vivo is an essential process for cellular functions. Transcription of ribosomal RNA (rRNA) genes is the rate-limiting step in ribosome biogenesis controlled by environmental conditions. Here, we investigated the role of folate antagonist on changes of DNA double-strand breaks (DSBs) landscape in mouse embryonic stem cells. A significant DSB enhancement was detected in the genome of these cells and a large majority of these DSBs were found in rRNA genes. Furthermore, spontaneous DSBs in cells under folate deficiency conditions were located exclusively within the rRNA gene units, representing a H3K4me1 hallmark. Enrichment H3K4me1 at the hot spots of DSB regions enhanced the recruitment of upstream binding factor (UBF) to rRNA genes, resulting in the increment of rRNA genes transcription. Supplement of folate resulted in a restored UBF binding across DNA breakage sites of rRNA genes, and normal rRNA gene transcription. In samples from neural tube defects (NTDs) with low folate level, up-regulation of rRNA gene transcription was observed, along with aberrant UBF level. Our results present a new view by which alterations in folate levels affects DNA breakage through epigenetic control leading to the regulation of rRNA gene transcription during the early stage of development.

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trans-splicing in nematodes

Nilsen¹

1989

Experimental Parasitology

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Organization and expression of 5S rRNA genes in the parasitic nematode,Brugia malayi

Cited by 12 publications

References 25 publications

Detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction-based assay.

Detection of the filarial parasite Mansonella streptocerca in skin biopsies by a nested polymerase chain reaction-based assay.

Folate deficiency facilitates recruitment of upstream binding factor to hot spots of DNA double-strand breaks of rRNA genes and promotes its transcription

trans-splicing in nematodes

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