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1.
Mol Biol (Mosk) ; 54(1): 78-86, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32163391

RESUMO

Short Interspersed Elements (SINEs) are mobile genetic elements of higher eukaryotes, which originated during evolution from various tRNAs and less often from 5S rRNA and 7SL RNA. Similar to the genes of these RNAs, SINEs are transcribed by RNA polymerase III. The transcripts of some mammalian SINEs have an ability to undergo AAUAAA-dependent polyadenylation, which is unique for the RNA polymerase III transcripts. It is well known that this polyadenylation of many RNA polymerase II transcripts (e.g., mRNAs) increases their lifetime in the cell. The aim of this work is to examine whether the stability of SINE transcripts increases as a result of AAUAAA-dependent polyadenylation. HeLa cells were transfected with SINE DNA, both containing and not containing the polyadenylation signal (AATAAA). One day later, the transcription was inhibited by actinomycin D, and the decrease in the level of the SINE transcripts was monitored by northern hybridization. For all the eight studied SINEs, the half-life of nonpolyadenylated transcripts was 20-30 minutes, and for polyadenylated transcripts, this parameter exceeded 3 hours. Interestingly, the insertion of an additional 80-bp DNA fragment into the middle region of B2 SINE did not significantly reduce the stability of the polyadenylated transcripts. It is most likely that the increase in the lifetime of the polyadenylated SINE transcripts is due to the fact that the poly(A) tail interacts with the poly(A)-binding proteins (PABPs), thus protecting the RNA from degradation by the exonucleases acting from the 3'-end. The results make it possible to design SINE-based vectors intended for the expression of short noncoding RNAs, which are stable in a cell due to polyadenylation.


Assuntos
Poliadenilação , RNA Polimerase III/metabolismo , Estabilidade de RNA , RNA de Transferência/química , RNA de Transferência/metabolismo , Elementos Nucleotídeos Curtos e Dispersos/genética , Transcrição Gênica , Animais , Células HeLa , Humanos , RNA de Transferência/genética
2.
Mol Biol (Mosk) ; 51(2): 262-273, 2017.
Artigo em Russo | MEDLINE | ID: mdl-28537233

RESUMO

Polyadenylation is the non-template addition of adenosine nucleotides at the 3'-end of RNA, which occurs after transcription and generates a poly(A) tail up to 250-300 nucleotides long. In the first section of our review, we consider the classical process of mRNA 3'-terminus formation, which involves the cleavage of the transcript synthesized by RNA polymerase II and the associated poly(A) tail synthesis by canonical polyadenylate polymerase. Nucleotide sequences needed for mRNA cleavage and poly(A) tail synthesis, in particular the AAUAAA polyadenylation signal, as well as numerous proteins and their complexes involved in mRNA cleavage and polyadenylation, is described in detail. The significance of the poly(A) tail for prolonging mRNA lifetime and stimulating their translation is discussed. Data presented in the second section demonstrate that RNA transcribed by RNA polymerase III from certain SINEs (Short Interspersed Elements) can undergo AAUAAA-dependent polyadenylation. The structural and functional features of RNA polymerase III determine the unusual character of polyadenylation of RNAs synthesized by this enzyme. The history of recent developments in this area of study have been described in greater detail, in particular the discovery of AAUAAA-dependent polyadenylation of RNA synthesized by RNA polymerase III, which has not been discussed previously. Data on AAUAAA-independent polyadenylation catalyzed by noncanonical TRAMP poly(A)-polymerases (Trf4 and Trf5) have been presented in the third section. These enzymes promote rapid degradation of RNAs by adding a short poly(A) tail to them. This mechanism enables the recognition, poly(A)-marking, and elimination of incorrectly folded noncoding transcripts (e.g. ribosomal and transfer RNAs).


Assuntos
Poli A/biossíntese , Poliadenilação/fisiologia , RNA Mensageiro/biossíntese , Animais , Humanos , Poli A/genética , RNA Mensageiro/genética
3.
Mol Biol (Mosk) ; 42(6): 977-89, 2008.
Artigo em Russo | MEDLINE | ID: mdl-19140317

RESUMO

We have isolated and characterised sequences of a SINE family specific for squamate reptiles from a genome of lacertid lizard that we called Squam1. Copies are 360-390 bp in length and share a significant similarity with tRNA gene sequence on its 5'-end. This family was also detected by us in DNA of representatives of varanids, iguanids (anolis), gekkonids, and snakes. No signs of it were found in DNA of mammals, birds, amphibians, and crocodiles. Detailed analysis of primary structure of the retroposons obtained by us from genomic libraries or GenBank sequences was carried out. Most taxa possess 2-3 subfamilies of the SINE in their genomes with specific diagnostic features in their primary structure. Individual variability of copies in different families is about 85% and is just slightly lower on the genera level. Comparison of consensus sequences on family level reveals a high degree of structural similarity with a number of specific apomorphic features which makes it a useful marker of phylogeny for this group of reptiles. Snakes do not show specific affinity to varanids when compared to other lizards, as it was suggested earlier.


Assuntos
Evolução Molecular , Filogenia , Répteis/genética , Retroelementos/genética , Animais , Marcadores Genéticos/genética , RNA de Transferência/genética
5.
Mol Biol (Mosk) ; 40(1): 74-83, 2006.
Artigo em Russo | MEDLINE | ID: mdl-16523694

RESUMO

Copies of two repetitive elements of the genome of common tree shrew (Tupaia glis) were cloned and sequenced. The first element, Tu III, is a approximately 260 bp long short interspersed element (SINE) with the 5'-end derived from glycine RNA. Tu III carries long polypurine- and polypyrimidine-rich tracts, which may contribute to the specific secondary structure of Tu III RNA. This SINE was also found in the genome of smooth-tailed tree shrew of another genus (Dendrogale). Tu III seems to be confined to the order Scandentia (tree shrews) since it was not found in DNA of other tested mammals. The second element Tu-SAT1 is a tandem repeat with a monomer length of 365 bp. Some properties of its nucleotide sequence suggest that Tu-SAT1 is a centromeric satellite.


Assuntos
DNA Satélite/genética , Genoma , Sequências Repetitivas de Ácido Nucleico , Tupaiidae/genética , Animais , Sequência de Bases , Dados de Sequência Molecular , Homologia de Sequência do Ácido Nucleico , Elementos Nucleotídeos Curtos e Dispersos
6.
Mamm Genome ; 12(10): 779-86, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11668393

RESUMO

Four tRNA-related SINE families were isolated from the genome of the shrew Sorex araneus (SOR element), mole Mogera robusta (TAL element), and hedgehog Mesechinus dauuricus (ERI-1 and ERI-2 elements). Each of these SINEs families is specific for a single Insectivora family: SOR, for Soricidae (shrews); TAL, for Talpidae (moles and desmans); ERI-1 and ERI-2, for Erinaceidae (hedgehogs). There is a long polypyrimidine region (TC-motif) in TAL, ERI-1, and ERI-2 elements located immediately upstream of an A-rich tail with polyadenylation signals (AATAAA) and an RNA polymerase III terminator (T(4-6)) or TCT(3-4)). Ten out of 14 analyzed mammalian tRNA-related SINE families have an A-rich tail similar to that of TAL, ERI-1, and ERI-2 elements. These elements were assigned to class T+. The other four SINEs including SOR element have no polyadenylation signal and transcription terminator in their A-rich tail and were assigned to class T-. Class T+ SINEs occur only in mammals, and most of them have a long polypyrimidine region. Possible models of retroposition of class T+ and T- SINEs are discussed.


Assuntos
Eulipotyphla/genética , Conformação de Ácido Nucleico , Poli A/genética , Elementos Nucleotídeos Curtos e Dispersos/genética , Animais , Sequência de Bases , Clonagem Molecular , Sequência Consenso/genética , Sequência Conservada/genética , Ouriços/genética , Dados de Sequência Molecular , Toupeiras/genética , Família Multigênica/genética , Poli A/química , Poli A/metabolismo , RNA Polimerase III/metabolismo , RNA de Transferência/química , RNA de Transferência/genética , RNA de Transferência/metabolismo , Sequências Reguladoras de Ácido Nucleico/genética , Musaranhos/genética
8.
FEBS Lett ; 457(3): 409-13, 1999 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-10471819

RESUMO

Most short interspersed elements (SINEs) in eukaryotic genomes originate from tRNA and have internal promoters for RNA polymerase III. The promoter contains two boxes (A and B) spaced by approximately 33 bp. We used oligonucleotide primers specific to these boxes to detect SINEs in the genomic DNA by polymerase chain reaction (PCR). Appropriate DNA fragments were revealed by PCR in 30 out of 35 eukaryotic species suggesting the wide distribution of SINEs. The PCR products were used for hybridization screening of genomic libraries which resulted in identification of four novel SINE families. The application of this approach is illustrated by discovery of a SINE family in the genome of the bat Myotis daubentoni. Members of this SINE family termed VES have an additional B-like box, a putative polyadenylation signal and RNA polymerase III terminator.


Assuntos
Células Eucarióticas/fisiologia , Genoma , Mamíferos/genética , Reação em Cadeia da Polimerase/métodos , Elementos Nucleotídeos Curtos e Dispersos/genética , Animais , Sequência de Bases , Gatos , Bovinos , Quirópteros/genética , Primers do DNA/genética , Cães , Ouriços/genética , Humanos , Hibridização In Situ/métodos , Camundongos , Dados de Sequência Molecular , Toupeiras/genética , Regiões Promotoras Genéticas , RNA Polimerase III/genética , RNA de Transferência/genética , Coelhos , Homologia de Sequência do Ácido Nucleico , Musaranhos/genética
10.
Genetika ; 32(5): 621-8, 1996 May.
Artigo em Russo | MEDLINE | ID: mdl-8755036

RESUMO

Gene expression was compared in a metastatic (VMR-Liv) neoplastic cell line and a related nonmetastatic (VMR-O) neoplastic cell line by means of the differential display method. A fragment of cDNA corresponding to the tag7 gene, differentially expressed in the metastatic cell line, was isolated. The full-length tag7 cDNA was cloned and its nucleotide sequence was determined. No homology between the tag7 gene and known sequences was revealed. tag7 gene transcription was studied in some tumors, cell lines, and normal mouse organs.


Assuntos
Regulação Neoplásica da Expressão Gênica/fisiologia , Oncogenes , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Clonagem Molecular , Camundongos , Camundongos Endogâmicos A , Dados de Sequência Molecular , Metástase Neoplásica , Reação em Cadeia da Polimerase/métodos , Valores de Referência , Análise de Sequência de DNA/métodos , Transcrição Gênica , Células Tumorais Cultivadas
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