Effect of undermethylation on mRNA cytoplasmic appearance and half-life.

Camper, Sally A.; Albers, Robert J.; Coward, James K.; Rottman, Fritz M.

doi:10.1128/mcb.4.3.538

Cited by 83 publications

(51 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This hypothesis is supported by the similarity between the m6A consensus sequences in both eucaryotic and viral RNA and the weakly conserved branch point sequence YNCU(G/A)AC used in intron removal (18,27,40). Camper et al (5) used the mRNA methylation inhibitor S-tubercidinyl homocysteine to measure the effects of undermethylation on the half-life and cytoplasmic appearance of poly(A)+ RNA in HeLa cells. A significant effect on processing and/or transport of undermethylated mRNA occurred with a delay in its appearance in the cytoplasm, whereas no significant alteration in the cytoplasmic half-life of undermethylated mRNA was observed.…”

mentioning

confidence: 80%

N6-methyladenosine residues in an intron-specific region of prolactin pre-mRNA.

Carroll¹,

Narayan²,

Rottman³

1990

Mol. Cell. Biol.

Self Cite

View full text Add to dashboard Cite

N6-methyladenosine (m6A) residues occur at internal positions in most cellular and viral RNAs; both heterogeneous nuclear RNA and mRNA are involved. This modffication arises by enzymatic transfer of a methyl group from S-adenosylmethionine to the central adenosine residue in the canonical sequence G/AAC. Thus suggested following the precise localization of m6A in Rous sarcoma virus (18). In that molecule, the modified residues were found bracketing the src splice acceptor site and therefore may influence in some way the accuracy and/or efficiency of processing. Methylation of internal adenosine residues of eucaryotic cell RNA also takes place in the nucleus, as evidenced by the demonstration of m6A in eucaryotic cell heterogeneous nuclear RNA (24). However, previous analysis indicated a conservation of m6A residues during processing and transport to the cytoplasm, suggesting that this modification occurs mainly within exon regions (19). It was therefore of great interest to determine whether m6A occurs in intron-specific regions of eucaryotic precursor RNA. This analysis would identify the temporal relationship between transcription, methylation, and nuclear processing and may assist in developing a concept for the role of this posttranscriptional modification in eucaryotic RNA biogenesis.Attempts have been made to determine the influence of m6A on processing of gene transcripts. Earlier studies with cycloleucine, an inhibitor of S-adenosylmethionine synthetase, suggested that m6A affects the splicing of avian sarcoma virus genomic RNA (34) and processing of CHO cell mRNA (2). This hypothesis is supported by the similarity between the m6A consensus sequences in both eucaryotic and viral RNA and the weakly conserved branch point sequence YNCU(G/A)AC used in intron removal (18,27,40). Camper et al. (5) used the mRNA methylation inhibitor S-tubercidinyl homocysteine to measure the effects of undermethylation on the half-life and cytoplasmic appearance of poly(A)+ RNA in HeLa cells. A significant effect on processing and/or transport of undermethylated mRNA occurred with a delay in its appearance in the cytoplasm, whereas no significant alteration in the cytoplasmic half-life of undermethylated mRNA was observed.

show abstract

mentioning

confidence: 80%

N6-methyladenosine residues in an intron-specific region of prolactin pre-mRNA.

Carroll¹,

Narayan²,

Rottman³

1990

Mol. Cell. Biol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…These experiments suggest an involvement of m6A in RNA processing events or in the transport of mRNA from the nucleus to the cytoplasm (6,13,35). It is not clear from these studies, however, that the effect of the inhibitors is directly related to the methylation state of the mRNA being examined.…”

mentioning

confidence: 99%

Precise localization of m6A in Rous sarcoma virus RNA reveals clustering of methylation sites: implications for RNA processing.

Kane¹,

Beemon²

1985

Mol. Cell. Biol.

169

306

View full text Add to dashboard Cite

N6-methyladenosine (m6A) residues are present as internal base modifications in most higher eucaryotic mRNAs; however, the biological function of this modification is not known. We describe a method for localizing and quantitating m6A within a large RNA In addition to having 5'-methylated cap structures, many eucaryotic mRNAs contain internal methylated bases. N6-methyladenosine (m6A), the major form of modified nucleoside, has been detected in most higher eucaryotic cell mRNAs, in viral mRNAs, and in the virion RNA of retroviruses (2). Methylation of internal adenosines occurs in the nucleus very rapidly after synthesis of the heterogeneous nuclear RNA precursor to mRNA and before the RNA is spliced (9, 28). While the function of this internal methylation is not known, several observations suggest a significant role for m6A in RNA metabolism.Some implications for the function of internal base modifications come from methylation inhibition studies, using either cycloleucine or S-tubercidinylhomocysteine to block internal methylation of RNA. These experiments suggest an involvement of m6A in RNA processing events or in the transport of mRNA from the nucleus to the cytoplasm (6, 13, 35). It is not clear from these studies, however, that the effect of the inhibitors is directly related to the methylation state of the mRNA being examined. Secondary effects of the drugs have not been ruled out. Furthermore, the requirement for internal methylation in mRNA is not absolute, as mature messages without any detectable m6A residues do exist, including globin and histone mRNAs (24,27).In all cases characterized to date, m6A occurs only in the sequences Gm6AC and Am6AC (7,12,31,38). Preliminary localization studies with specific RNAs have determined that the distribution of m6A within a molecule is nonrandom.Rous sarcoma virus (RSV), for example, has an average of 10 to 15 m6A residues per virion RNA molecule (4, 14, 36).These methylated bases have been detected only in the 3' half of the genomic RNA (4), even though sequence analysis shows that putative methylation sites (GAC and AAC) are widely dispersed throughout the molecule (32). Likewise, internal methylation of bovine prolactin mRNA is confined to the 3' two-thirds of the message, with a high concentration of m6A in the 3' noncoding region (17). Simian virus 40 * Corresponding author.(SV40) late mRNAs, on the other hand, each contain an average of three m6As, all near the 5' ends of those messages in translated sequences (7). Adenovirus mRNAs are methylated in the 5' two-thirds of the molecules, and m6As seem, in this system, to be conserved during mRNA processing (9, 33).We have developed a method for directly identifying m6A residues within the genomic RNA of RSV. We have precisely mapped seven such sites in the genome, all within protein coding regions. In addition, we have analyzed the extent of modification at individual methylation sites. Earlier studies with SV40 (7) and with RSV (12) suggest that methylation at some specific sites is heterogeneous, with bas...

show abstract

“…The earlier reports of the inability of NPC and S- tubercidinyl homocysteine to inhibit the guanine-7-methylation in cap structure [6,8], may have been due to the analysis of poly A selected RNA. We have found that if the mRNA is not guanine-7-methylated it does not bind to ribosomes, i.e.…”

Section: Discussionmentioning

confidence: 99%

“…Among the most important of these methylations is that of the 7-position of the guanine base, as the cap is not functional without it [2,5]. The roles of the other cap methylations and the methylation of internal bases such as N6-methyladenosine are not clear, but may play a role in processing and/or transport to the cytosol [6].…”

Section: Introductionmentioning

confidence: 99%

Adenosine analogs inhibit the guanine‐7‐methylation of mRNA cap structures

Oxenrider

Sitz

1993

FEBS Letters

View full text Add to dashboard Cite

The adenosine analogs neplanocin A and deazaneplanocin A were observed to inhibit the in vivo guanine-7-methylation of mRNA cap structure using a new assay for hypomethylated RNA. Treatment of cultured mammalian cells with these adenosine analogs resulted in the same extent of hypomethylation of cap structure as did ethionine injection in mice. Neplanocin A and its non-metabolizable analog 3deazaneplanocin A show the same maximal level of inhibition of methylation suggesting that these adenosine analogs exert their effects by elevating S-adenosylhomocysteine levels rather than by conversion to other inhibitory compounds.

show abstract

Effect of undermethylation on mRNA cytoplasmic appearance and half-life.

Abstract: S-Tubercidinylhomocysteine (STH) is a structural analog of S-adenosylhomocysteine and a potent inhibitor of S-adenosylmethionine-dependent methyltransferase reactions. We investigated the effects of STH on HeLa cell mRNA metabolism. Dual

Cited by 83 publications

References 30 publications

N6-methyladenosine residues in an intron-specific region of prolactin pre-mRNA.

N6-methyladenosine residues in an intron-specific region of prolactin pre-mRNA.

Precise localization of m6A in Rous sarcoma virus RNA reveals clustering of methylation sites: implications for RNA processing.

Adenosine analogs inhibit the guanine‐7‐methylation of mRNA cap structures

Contact Info

Product

Resources

About