Prp24: Difference between revisions

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Prp24 coimmunoprecipitates with free U6 and U4/U6 di-snRNP, indicating that it is closely associated with these structures <ref name="Shannon"/><ref name="Ghetti">PMID:7585243</ref>. Initial investigation revealed that Prp24 binds within the 30-56 nucleotide region of free U6, as well as to stem II of U4/U6 in the 39-56 and 67-70 nucleotide regions of U6 <ref name="Ghetti"/>. Further investigation of the structure showed that Prp24 very likely binds directly to the 40-43 nucleotides of U6 based on chemical modification of naked U6 snRNA compared to free U6 snRNP<ref name="Jandrositz"/>.

The main function of Prp24 seems to be directly related to formation of the U4/U6 complex, particularly based on the evidence that Prp24 is present in U6 and U4/U6, but not U4/U6.U5 <ref name="Shannon"/><ref name="Ghetti"/><ref name="Jandrositz"/>. Prp24 greatly increases the rate and efficiency of U4/U6 annealing <ref ~~nam~~"Raghunathan">PMID:9452384</ref> and mutations in Prp24 have been shown to prevent the formation of the U4/U6 di-snRNP <ref name="Lygerou">PMID:10022888</ref>. Although the exact mechanism by which Prp24 promotes annealing of U4 and U6, it has been suggested that Prp24 may stabilize the secondary structure of U6 to allow it to interact with U4 in order to allow formation of U4/U6 <ref name="Vidaver"/>.

The main function of Prp24 seems to be directly related to formation of the U4/U6 complex, particularly based on the evidence that Prp24 is present in U6 and U4/U6, but not U4/U6.U5 <ref name="Shannon"/><ref name="Ghetti"/><ref name="Jandrositz"/>. Prp24 greatly increases the rate and efficiency of U4/U6 annealing <ref name="Raghunathan">PMID:9452384</ref> and mutations in Prp24 have been shown to prevent the formation of the U4/U6 di-snRNP <ref name="Lygerou">PMID:10022888</ref>. Although the exact mechanism by which Prp24 promotes annealing of U4 and U6, it has been suggested that Prp24 may stabilize the secondary structure of U6 to allow it to interact with U4 in order to allow formation of U4/U6 <ref name="Vidaver"/>.

The interactions of Prp24 with U6 and U4/U6 are very important in proper spliceosome assembly, as evidenced by mutations in Prp24 that suppress mutations in U6 or U4. Mutations in RRM 2 and RRM 3 suppress the effects of mutations in the 3' stem of U6, in a region termed the telestem <ref name="Vidaver"/>. A later study showed that RRM 1 binds with high affinity to U6 and is important in interactions with mutations in the 3' region of U6 <ref name="Kwan"/>. Mutations in two RNP consensus domains of Prp24 suppress the effects of mutations in U4 in the stem II region of U4/U6 <ref name="Shannon"/>. Truncation and deletion of internal segments of U6 showed that the central region of U6 is the most important region for interaction with Prp24 and that RRM 1 and RRM 2 are the likely portions of Prp24 that interact with U6 in this region <ref name="Kwan"/>. Deletion of conserved residues in the C-terminal domain of Prp24 caused temperature sensitive growth and reduced levels of U4/U6, suggesting that this region too, containing the fourth RRM, is important for interactions in assembly of the spliceosome <ref name="Rader"/>.

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 Prp24 coimmunoprecipitates with free U6 and U4/U6 di-snRNP, indicating that it is closely associated with these structures <ref name="Shannon"/><ref name="Ghetti">PMID:7585243</ref>.  Initial investigation revealed that Prp24 binds within the 30-56 nucleotide region of free U6, as well as to stem II of U4/U6 in the 39-56 and 67-70 nucleotide regions of U6 <ref name="Ghetti"/>.  Further investigation of the structure showed that Prp24 very likely binds directly to the 40-43 nucleotides of U6 based on chemical modification of naked U6 snRNA compared to free U6 snRNP<ref name="Jandrositz"/>.
-The main function of Prp24 seems to be directly related to formation of the U4/U6 complex, particularly based on the evidence that Prp24 is present in U6 and U4/U6, but not U4/U6.U5 <ref name="Shannon"/><ref name="Ghetti"/><ref name="Jandrositz"/>.  Prp24 greatly increases the rate and efficiency of U4/U6 annealing <ref nam"Raghunathan">PMID:9452384</ref> and mutations in Prp24 have been shown to prevent the formation of the U4/U6 di-snRNP <ref name="Lygerou">PMID:10022888</ref>.  Although the exact mechanism by which Prp24 promotes annealing of U4 and U6, it has been suggested that Prp24 may stabilize the secondary structure of U6 to allow it to interact with U4 in order to allow formation of U4/U6 <ref name="Vidaver"/>.
+The main function of Prp24 seems to be directly related to formation of the U4/U6 complex, particularly based on the evidence that Prp24 is present in U6 and U4/U6, but not U4/U6.U5 <ref name="Shannon"/><ref name="Ghetti"/><ref name="Jandrositz"/>.  Prp24 greatly increases the rate and efficiency of U4/U6 annealing <ref name="Raghunathan">PMID:9452384</ref> and mutations in Prp24 have been shown to prevent the formation of the U4/U6 di-snRNP <ref name="Lygerou">PMID:10022888</ref>.  Although the exact mechanism by which Prp24 promotes annealing of U4 and U6, it has been suggested that Prp24 may stabilize the secondary structure of U6 to allow it to interact with U4 in order to allow formation of U4/U6 <ref name="Vidaver"/>.
 The interactions of Prp24 with U6 and U4/U6 are very important in proper spliceosome assembly, as evidenced by mutations in Prp24 that suppress mutations in U6 or U4.  Mutations in RRM 2 and RRM 3 suppress the effects of mutations in the 3' stem of U6, in a region termed the telestem <ref name="Vidaver"/>.  A later study showed that RRM 1 binds with high affinity to U6 and is important in interactions with mutations in the 3' region of U6 <ref name="Kwan"/>.  Mutations in two RNP consensus domains of Prp24 suppress the effects of mutations in U4 in the stem II region of U4/U6 <ref name="Shannon"/>.  Truncation and deletion of internal segments of U6 showed that the central region of U6 is the most important region for interaction with Prp24 and that RRM 1 and RRM 2 are the likely portions of Prp24 that interact with U6 in this region <ref name="Kwan"/>.  Deletion of conserved residues in the C-terminal domain of Prp24 caused temperature sensitive growth and reduced levels of U4/U6, suggesting that this region too, containing the fourth RRM, is important for interactions in assembly of the spliceosome <ref name="Rader"/>.