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Aberrant methylation and associated transcriptional mobilization of Alu elements contributes to genomic instability in hypoxia.

Pal A, Srivastava T, Sharma MK, Mehndiratta M, Das P, Sinha S, Chattopadhyay P - J. Cell. Mol. Med. (2010)

Bottom Line: Because a majority of the cytosine-phosphate-guanine (CpG) islands are found within the repeat elements of DNA, and are usually methylated under normoxic conditions, we suggested that retrotransposable Alu or short interspersed nuclear elements (SINEs) which show altered methylation and associated changes of gene expression during hypoxia, could be associated with genomic instability.U87MG glioblastoma cells were cultured in 0.1% O₂ for 6 weeks and compared with cells cultured in 21% O₂ for the same duration.Our results show that aberrant methylation leading to increased transcription of SINE and reverse transcriptase associated LINE elements could lead to increased genomic instability in hypoxia.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India.

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Related in: MedlinePlus

SINE (alu) and LINE transcript levels: Relative expression of (A) SINE and (B) LINE in U87MG and SaOS2 cell lines under normoxia, hypoxia and 4-week revert to normoxia by real-time PCR. The SINE and LINE expression are markedly increased in 6-week hypoxia as shown by average values from two biological replicates. Representative photographs of RT-PCR are shown in inset. The values are normalized with respect to b-actin.
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fig02: SINE (alu) and LINE transcript levels: Relative expression of (A) SINE and (B) LINE in U87MG and SaOS2 cell lines under normoxia, hypoxia and 4-week revert to normoxia by real-time PCR. The SINE and LINE expression are markedly increased in 6-week hypoxia as shown by average values from two biological replicates. Representative photographs of RT-PCR are shown in inset. The values are normalized with respect to b-actin.

Mentions: Real-time PCR and RT-PCR was done with cDNA prepared from total RNA extracted from cells cultured in hypoxia, normoxia and hypoxia of 6 weeks reverted to 4-week normoxia. Average values of two biological replicates are shown. After 6-week hypoxia, there was a 9.57-fold increase in relative expression of SINE in U87MG cells as compared to normoxia (P= 0.0008). In case of SaOS2 the increase in the expression level is approximately 6.30-fold in hypoxia (P= 0.0004). SINE transcripts levels increased only by 1.29-fold in U87MG and 1.36-fold in SaOS2 revertents (Fig. 2A).


Aberrant methylation and associated transcriptional mobilization of Alu elements contributes to genomic instability in hypoxia.

Pal A, Srivastava T, Sharma MK, Mehndiratta M, Das P, Sinha S, Chattopadhyay P - J. Cell. Mol. Med. (2010)

SINE (alu) and LINE transcript levels: Relative expression of (A) SINE and (B) LINE in U87MG and SaOS2 cell lines under normoxia, hypoxia and 4-week revert to normoxia by real-time PCR. The SINE and LINE expression are markedly increased in 6-week hypoxia as shown by average values from two biological replicates. Representative photographs of RT-PCR are shown in inset. The values are normalized with respect to b-actin.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4373486&req=5

fig02: SINE (alu) and LINE transcript levels: Relative expression of (A) SINE and (B) LINE in U87MG and SaOS2 cell lines under normoxia, hypoxia and 4-week revert to normoxia by real-time PCR. The SINE and LINE expression are markedly increased in 6-week hypoxia as shown by average values from two biological replicates. Representative photographs of RT-PCR are shown in inset. The values are normalized with respect to b-actin.
Mentions: Real-time PCR and RT-PCR was done with cDNA prepared from total RNA extracted from cells cultured in hypoxia, normoxia and hypoxia of 6 weeks reverted to 4-week normoxia. Average values of two biological replicates are shown. After 6-week hypoxia, there was a 9.57-fold increase in relative expression of SINE in U87MG cells as compared to normoxia (P= 0.0008). In case of SaOS2 the increase in the expression level is approximately 6.30-fold in hypoxia (P= 0.0004). SINE transcripts levels increased only by 1.29-fold in U87MG and 1.36-fold in SaOS2 revertents (Fig. 2A).

Bottom Line: Because a majority of the cytosine-phosphate-guanine (CpG) islands are found within the repeat elements of DNA, and are usually methylated under normoxic conditions, we suggested that retrotransposable Alu or short interspersed nuclear elements (SINEs) which show altered methylation and associated changes of gene expression during hypoxia, could be associated with genomic instability.U87MG glioblastoma cells were cultured in 0.1% O₂ for 6 weeks and compared with cells cultured in 21% O₂ for the same duration.Our results show that aberrant methylation leading to increased transcription of SINE and reverse transcriptase associated LINE elements could lead to increased genomic instability in hypoxia.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India.

Show MeSH
Related in: MedlinePlus