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Search results 1 to 21 out of 21 for Rrm1

Category restricted to ProteinDomain (x)

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Categories

Category: ProteinDomain
Type Details Score
Protein Domain
Type: Family
Description: Ribonucleotide reductase (RNR, ) [, ]catalyzes the reductivesynthesis of deoxyribonucleotides from their corresponding ribonucleotides. It provides the precursors necessary for DNA synthesis. RNRs divide into three classes on the basis of their metallocofactor usage. Class I RNRs, found in eukaryotes, bacteria, bacteriophage and viruses, use a diiron-tyrosyl radical, Class II RNRs, found in bacteria, bacteriophage, algae and archaea, use coenzyme B12 (adenosylcobalamin, AdoCbl). Class III RNRs, found in anaerobic bacteria and bacteriophage, use an FeS cluster and S-adenosylmethionine to generate a glycyl radical. Many organisms have more than one class of RNR present in their genomes. Ribonucleotide reductase is an oligomeric enzyme composed of a large subunit (700 to 1000 residues) and a small subunit (300 to 400 residues) - class II RNRs are less complex, using the small molecule B12 in place of the small chain []. The reduction of ribonucleotides to deoxyribonucleotides involves the transfer of free radicals, the function of each metallocofactor is to generate an active site thiyl radical. This thiyl radical then initiates the nucleotide reduction process by hydrogen atom abstraction from the ribonucleotide []. The radical-based reaction involves five cysteines: two of these are located at adjacent anti-parallel strands in a new type of ten-stranded alpha/β-barrel; two others reside at the carboxyl end in a flexible arm; and the fifth, in a loop in the centre of the barrel, is positioned to initiate the radical reaction []. There are several regions of similarity in the sequence of the large chain of prokaryotes, eukaryotes and viruses spread across 3 domains: an N-terminal domain common to the mammalian and bacterial enzymes; a C-terminal domain common to the mammalian and viral ribonucleotide reductases; and a central domain common to all three [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif (RRM) of RBM27. Although the specific function of the RRM in RBM27 remains unclear, it shows high sequence similarity with RRM1 of RBM26, which functions as a cutaneous lymphoma (CL)-associated antigen [].
Protein Domain
Type: Family
Description: The THAP domain is a C2CH module with zinc-dependent sequence-specific DNA-binding activity []. Several THAP domain-containing proteins have been described. THAP3 is a component of a THAP1/THAP3-HCFC1-OGT complex that is required for the regulation of the transcriptional activity of the cell cycle-specific gene RRM1 [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 1 (RRM1) of RBM40 (also known as U11/U12-65K). RBM40 serves as a bridging factor between the U11 and U12 snRNPs []. It contains two repeats of an RNA recognition motif (RRM), connected by a linker that includes a proline-rich region. It binds to the U11-associated 59K protein via its RRM1 and employs the RRM2 to bind hairpin III of the U12 small nuclear RNA (snRNA). The proline-rich region might be involved in protein-protein interactions [].
Protein Domain
Type: Family
Description: RNPC3 serves as a bridging factor between the U11 and U12 snRNPs. It contains two RNA recognition motifs (RRMs), connected by a linker that includes a proline-rich region. It binds to the U11-associated 59K protein via its RRM1 and employs the RRM2 to bind hairpin III of the U12 small nuclear RNA (snRNA). The proline-rich region might be involved in protein-protein interactions [, ]. RBM41 contains only one RRM. Its biological function remains unclear.
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 3 (RRM3) of heterogeneous nuclear ribonucleoprotein H3 (hnRNP H3). hnRNP H3 (also termed hnRNP 2H9) is a nuclear RNA binding protein that belongs to the hnRNP H protein family that also includes hnRNP H, hnRNP H2, and hnRNP F. This family is involved in mRNA processing and exhibit extensive sequence homology. Little is known about the functions of hnRNP H3 except for its role in the splicing arrest induced by heat shock [, ]. The typical hnRNP H proteins contain contain three RNA recognition motifs (RRMs), except for hnRNP H3, in which the RRM1 is absent. RRM1 and RRM2 are responsible for the binding to the RNA at DGGGD motifs, and they play an important role in efficiently silencing the exon. Members in this family can regulate the alternative splicing of the fibroblast growth factor receptor 2 (FGFR2) transcripts, and function as silencers of FGFR2 exon IIIc through an interaction with the exonic GGG motifs. The lack of RRM1 could account for the reduced silencing activity within hnRNP H3. In addition, like other hnRNP H protein family members, hnRNP H3 has an extensive glycine-rich region near the C terminus, which may allow it to homo- or heterodimerize [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 2 (RRM2) of heterogeneous nuclear ribonucleoprotein H3 (hnRNP H3).hnRNP H3 (also termed hnRNP 2H9) is a nuclear RNA binding protein that belongs to the hnRNP H protein family that also includes hnRNP H, hnRNP H2, and hnRNP F. This family is involved in mRNA processing and exhibit extensive sequence homology. Little is known about the functions of hnRNP H3 except for its role in the splicing arrest induced by heat shock [, ]. The typical hnRNP H proteins contain contain three RNA recognition motifs (RRMs), except for hnRNP H3, in which the RRM1 is absent. RRM1 and RRM2 are responsible for the binding to the RNA at DGGGD motifs, and they play an important role in efficiently silencing the exon. Members in this family can regulate the alternative splicing of the fibroblast growth factor receptor 2 (FGFR2) transcripts, and function as silencers of FGFR2 exon IIIc through an interaction with the exonic GGG motifs. The lack of RRM1 could account for the reduced silencing activity within hnRNP H3. In addition, like other hnRNP H protein family members, hnRNP H3 has an extensive glycine-rich region near the C terminus, which may allow it to homo- or heterodimerize [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 1 (RRM1) of CELF-3, CELF-4, CELF-5, CELF-6, all of which belong to the CUGBP1 and ETR-3-like factors (CELF) or BRUNOL (Bruno-like) family of RNA-binding proteins [, ]. The CELF family members have three RRMs []. It has been shown that either RRM1 or RRM2 of CELF-4 are necessary and sufficient for muscle-specific splicing enhancer (MSE) RNA binding []. The human CELF family has six members, which can be divided into two subfamilies based on their phylogeny: CELF1-2 and CELF3-6. They all possess alternative splicing activity in the nucleus and all have cytoplasmic roles, including regulating mRNA adenylation status, stability, and translation in various cell types [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 3 (RRM3) of HuB. HuB (also known as ELAV-like protein 2 or Hel-N1) is one of the neuronal members of the Hu family []. The neuronal Hu proteins play important roles in neuronal differentiation, plasticity and memory. HuB is also expressed in gonads. It is up-regulated during neuronal differentiation of embryonic carcinoma P19 cells []. Like other Hu proteins, HuB contains three RNA recognition motifs (RRMs). RRM1 and RRM2 may cooperate in binding to an AU-rich RNA element (ARE). RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 3 (RRM3) of HuC (also known as ELAV-like protein 3), one of the neuronal members of the Hu family. The neuronal Hu proteins play important roles in neuronal differentiation, plasticity and memory []. Like other Hu proteins, HuC contains three RNA recognition motifs (RRMs). RRM1 and RRM2 may cooperate in binding to an AU-rich RNA element (ARE) []. The AU-rich element binding of HuC can be inhibited by flavonoids. RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 2 (RRM2) of HuB. HuB (also known as ELAV-like protein 2 or Hel-N1) is one of the neuronal members of the Hu family []. The neuronal Hu proteins play important roles in neuronal differentiation, plasticity and memory. HuB is also expressed in gonads. It is up-regulated during neuronal differentiation of embryonic carcinoma P19 cells []. Like other Hu proteins, HuB contains three RNA recognition motifs (RRMs). RRM1 and RRM2 may cooperate in binding to an AU-rich RNA element (ARE). RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 3 (RRM3) of HuD (also known as ELAV-like protein 4), one of the neuronal members of the Hu family. The neuronal Hu proteins play important roles in neuronal differentiation, plasticity and memory. HuD has been implicated in various aspects of neuronal function, such as the commitment and differentiation of neuronal precursors as well as synaptic remodeling in mature neurons []. HuD also functions as an important regulator of mRNA expression in neurons by interacting with AU-rich RNA element (ARE) and stabilizing multiple transcripts []. Moreover, HuD regulates the nuclear processing/stability of N-myc pre-mRNA in neuroblastoma cells []. Like other Hu proteins, HuD contains three RNA recognition motifs (RRMs). RRM1 and RRM2 may cooperate in binding to an ARE. RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 2 (RRM2) of HuR, also known as ELAV-like protein 1 (ELAV-1), the ubiquitously expressed Hu family member [, ]. HuR binds to AU-rich RNA element (ARE) in target mRNAs and stabilizes them against degradation. It also regulates the nuclear import of proteins []. It has a variety of biological functions mostly related to the regulation of cellular response to DNA damage and other types of stress. HuR has an anti-apoptotic function during early cell stress response []. HuR may be important in muscle differentiation, adipogenesis, suppression of inflammatory response and modulation of gene expression in response to chronic ethanol exposure and amino acid starvation [].Like other Hu proteins, HuR contains three RNA recognition motifs (RRMs). RRM1 and RRM2 may cooperate in binding to an AU-rich RNA element (ARE). RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions [].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 1 (RRM1) of polypyrimidine tract-binding protein 1 (PTBP1). PTBP1 (also known as PTB) is involved in numerous post-transcriptional steps in gene expression in both the nucleus and cytoplasm. It can act as a negative regulator of alternative splicing and as an activator of translation driven by IRESs (internal ribosome entry segments) []. It contains four RNA recognition motifs (RRM). RRM1 and RRM2 are independent from each other and separated by flexible linkers. By contrast, there is an unusual and conserved interdomain interaction between RRM3 and RRM4. It is widely held that only RRMs 3 and 4 are involved in RNA binding and RRM2 mediates PTB homodimer formation. However, new evidence shows that the RRMs 1 and 2 also contribute substantially to RNA binding. Moreover, PTB may not always dimerize to repress splicing. It is a monomer in solution [, ].
Protein Domain
Type: Family
Description: The beta (small) subunit of ribonucleotide reductase (RNR) is a member of a broad superfamily of ferritin-like diiron-carboxylate proteins. The RNR protein catalyzes the conversion of ribonucleotides to deoxyribonucleotides and is found in all eukaryotes, many prokaryotes, several viruses, and few archaea. The catalytically active form of RNR is a proposed alpha2-beta2 tetramer. The homodimeric alpha subunit (R1) contains the active site and redox active cysteines as well as the allosteric binding sites. The beta subunit (R2) contains a di-iron cluster that, in its reduced state, reacts with dioxygen to form a stable tyrosyl radical and a di-iron(III) cluster. This essential tyrosyl radical is proposed to generate a thiyl radical, located on a cysteine residue in the R1 active site that initiates ribonucleotide reduction. The beta subunit is composed of 10-13 helices, the eight longest helices form an α-helical bundle; some have two addition beta strands [, , , ].The beta-herpesvirus RNR R1 subunit homologues are catalytically inactive; the enzyme seem to function by inhibiting cellular adaptor protein RIP1 to block cellular signaling pathways involved in innate immunity and inflammation [].Yeast is unique in that it assembles both homodimers and heterodimers of RNR. The yeast heterodimer, Y2Y4, contains R2 (Y2) and a R2 homologue (Y4) that lacks the diiron centre and is proposed to only assist in cofactor assembly, and perhaps stabilize R1 (Y1) in its active conformation [, ]. In mammals, the active form of the enzyme is composed of two identical large subunits (RRM1) and two identical small subunits (RRM2 or its homologue RRM2B). RRM1 is the catalytic subunit, and RRM2 and RRM2B the regulatory subunits. RRM2B (also called p53R2) can be induced by p53 [, ].
Protein Domain
Type: Domain
Description: This entry represents the RNA recognition motif 1 (RRM1) of PSF.PSF is a member of the DBHS (Drosophila behavior human splicing) family. It participates in a wide range of gene regulatory processes and cellular response pathways. It has been shown to affect the alternative splicing of CD45 and Tau and regulate the 3' polyadenylation of mRNAs. It is often localised in the paraspeckles and may be involved in the nuclear retention of mRNAs. It is involved in translation and transcription. It can bind directly to DSBs and play a role in DNA repair. PSF can also be utilized as an essential host factor for viral RNA multiplication and replication [, ]. In addition to the common DHBS core, which encompasses RRM1 and RRM2, the protein-protein interaction NOPS domain and the coiled-coil domain, PSF features additional domains, such as a RGG motif and a proline-rich region in its N terminus []. DBHS (Drosophila behavior human splicing) family are characterised by a core domain arrangement consisting of tandem RNA recognition motifs (RRMs), a conserved intervening sequence referred to as a NONA/ParaSpeckle (NOPS) domain, and a ~100 amino acid coiled-coil domain. Its members include p54nrb (also known as NONO), PTB-associated splicing factor/splicing factor proline-glutamine rich (PSF or SFPQ) and PSPC1 (paraspeckle protein component 1). They are found in the nucleoplasm and can be triggered by binding to local high concentrations of various nucleic acids to form microscopically visible nuclear bodies, paraspeckles or large complexes such as DNA repair foci. They may also function cytoplasmically and on the cell surface in defined cell types. All three DBHS proteins are conserved throughout vertebrate species, while flies, worms, and yeast express a single DBHS protein [, ].
Protein Domain
Type: Domain
Description: This entry represents the NOPS domain and the C-terminal coiled-coil region of PSF (also known as SFPQ). The C-terminal coiled-coil region functions in mediating DBHS dimerization, while some surface-exposed basic residues within the NOPS domain may be involved in nucleic acid binding [].PSF is a member of the DBHS (Drosophila behavior human splicing) family. It participates in a wide range of gene regulatory processes and cellular response pathways. It has been shown to affect the alternative splicing of CD45 and Tau and regulate the 3' polyadenylation of mRNAs. It is often localised in the paraspeckles and may be involved in the nuclear retention of mRNAs. It is involved in translation and transcription. It can bind directly to DSBs and play a role in DNA repair. PSF can also be utilized as an essential host factor for viral RNA multiplication and replication [, ]. In addition to the common DHBS core, which encompasses RRM1 and RRM2, the protein-protein interaction NOPS domain and the coiled-coil domain, PSF features additional domains, such as a RGG motif and a proline-rich region in its N terminus []. DBHS (Drosophila behavior human splicing) family are characterised by a core domain arrangement consisting of tandem RNA recognition motifs (RRMs), a conserved intervening sequence referred to as a NONA/ParaSpeckle (NOPS) domain, and a ~100 amino acid coiled-coil domain. Its members include p54nrb (also known as NONO), PTB-associated splicing factor/splicing factor proline-glutamine rich (PSF or SFPQ) and PSPC1 (paraspeckle protein component 1). They are found in the nucleoplasm and can be triggered by binding to local high concentrations of various nucleic acids to form microscopically visible nuclear bodies, paraspeckles or large complexes such as DNA repair foci. They may also function cytoplasmically and on the cell surface in defined cell types. All three DBHS proteins are conserved throughout vertebrate species, while flies, worms, and yeast express a single DBHS protein [, ].
Protein Domain
Type: Family
Description: The beta (small) subunit of ribonucleotide reductase (RNR) is a member of a broad superfamily of ferritin-like diiron-carboxylate proteins. The RNR protein catalyzes the conversion of ribonucleotides to deoxyribonucleotides and is found in all eukaryotes, many prokaryotes, several viruses, and few archaea. The catalytically active form of RNR is a proposed alpha2-beta2 tetramer. The homodimeric alpha subunit (R1) contains the active site and redox active cysteines as well as the allosteric binding sites. The beta subunit (R2) contains a di-iron cluster that, in its reduced state, reacts with dioxygen to form a stable tyrosyl radical and a di-iron(III) cluster. This essential tyrosyl radical is proposed to generate a thiyl radical, located on a cysteine residue in the R1 active site that initiates ribonucleotide reduction. The beta subunit is composed of 10-13 helices, the eight longest helices form an α-helical bundle; some have two addition beta strands [, , , ].The beta-herpesvirus RNR R1 subunit homologues are catalytically inactive; the enzyme seem to function by inhibiting cellular adaptor protein RIP1 to block cellular signaling pathways involved in innate immunity and inflammation [].Yeast is unique in that it assembles both homodimers and heterodimers of RNR. The yeast heterodimer, Y2Y4, contains R2 (Y2) and a R2 homologue (Y4) that lacks the diiron centre and is proposed to only assist in cofactor assembly, and perhaps stabilize R1 (Y1) in its active conformation [, ]. In mammals, the active form of the enzyme is composed of two identical large subunits (RRM1) and two identical small subunits (RRM2 or its homologue RRM2B). RRM1 is the catalytic subunit, and RRM2 and RRM2B the regulatory subunits. RRM2B (also called p53R2) can be induced by p53 [, ].This entry includes the ribonucleoside-diphosphate reductase small subunit from Herpesviruses.
Protein Domain
Type: Domain
Description: The human CELF family has six members, which can be divided into two subfamilies based on their phylogeny: CELF1-2 and CELF3-6. This entry represents the RNA recognition motif 2 (RRM2) of CELF-1 and CELF-2 protein. CELF-1 and CELF-2 belong to the CELF (CUGBP and ETR-3 Like Factor)/Bruno-like protein family, whose members play important roles in the regulation of alternative splicing and translation. CELF-1 and CELF-2 share sequence similarity to the Drosophila Bruno protein and binds to the Bruno response elements (cis-acting sequences in the 3'-untranslated region (UTR) ofoskar mRNA) [].The human CELF-1 (also known as CUG-BP or BRUNOL-2) binds to RNA substrates and recruits PARN deadenylase []. It preferentially targets UGU-rich mRNA elements []. CELF-1 has been implicated in onset of type 1 myotonic dystrophy (DM1), a neuromuscular disease associated with an unstable CUG triplet expansion in the 3'-UTR (3'-untranslated region) of the DMPK (myotonic dystrophy protein kinase) gene [, ]. CELF-1 contain three highly conserved RNA recognition motifs (RRMs): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C terminus of the protein. The Xenopus homologue of CELF-1 is EDEN-BP (embryo deadenylation element-binding protein), which mediates sequence-specific deadenylation of Eg5 mRNA. It binds specifically to the EDEN motif in the 3'-untranslated regions of maternal mRNAs and targets these mRNAs for deadenylation and translational repression []. The two N-terminal RRMs of EDEN-BP are necessary for the interaction with EDEN as well as a part of the linker region (between RRM2 and RRM3). Oligomerization of EDEN-BP is required for specific mRNA deadenylation and binding []. CELF-2 (also known as CUGBP2 or ETR-3) shares high sequence identity with CELF-1, but shows different binding specificity; it binds preferentially to sequences with UG repeats and UGUU motifs. It also binds to the 3'-UTR of cyclooxygenase-2 messages, affecting both translation and mRNA stability, and binds to apoB mRNA, regulating its C to U editing []. CELF-2 also contains three highly conserved RRMs. It binds to RNA via the first two RRMs, which are also important for localization in the cytoplasm. The splicing activation or repression activity of CELF-2 on some specific substrates is mediated by RRM1/RRM2. Both, RRM1 and RRM2 of CELF-2, can activate cardiac troponin T (cTNT) exon 5 inclusion. In addition, CELF-2 possesses a typical arginine and lysine-rich nuclear localization signal (NLS) in the C terminus, within RRM3 [].
Protein Domain
Type: Domain
Description: The human CELF family has six members, which can be divided into two subfamilies based on their phylogeny: CELF1-2 and CELF3-6. This entry represents the RNA recognition motif 3 (RRM3) of CELF-1 andCELF-2 protein. CELF-1 and CELF-2 belong to the CELF (CUGBP and ETR-3 Like Factor)/Bruno-like protein family, whose members play important roles in the regulation of alternative splicing and translation. CELF-1 and CELF-2 share sequence similarity to the Drosophila Bruno protein and binds to the Bruno response elements (cis-acting sequences in the 3'-untranslated region (UTR) ofoskar mRNA) [].The human CELF-1 (also known as CUG-BP or BRUNOL-2) binds to RNA substrates and recruits PARN deadenylase []. It preferentially targets UGU-rich mRNA elements []. CELF-1 has been implicated in onset of type 1 myotonic dystrophy (DM1), a neuromuscular disease associated with an unstable CUG triplet expansion in the 3'-UTR (3'-untranslated region) of the DMPK (myotonic dystrophy protein kinase) gene [, ]. CELF-1 contain three highly conserved RNA recognition motifs (RRMs): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C terminus of the protein. The Xenopus homologue of CELF-1 is EDEN-BP (embryo deadenylation element-binding protein), which mediates sequence-specific deadenylation of Eg5 mRNA. It binds specifically to the EDEN motif in the 3'-untranslated regions of maternal mRNAs and targets these mRNAs for deadenylation and translational repression []. The two N-terminal RRMs of EDEN-BP are necessary for the interaction with EDEN as well as a part of the linker region (between RRM2 and RRM3). Oligomerization of EDEN-BP is required for specific mRNA deadenylation and binding []. CELF-2 (also known as CUGBP2 or ETR-3) shares high sequenceidentity with CELF-1, but shows different binding specificity; it binds preferentially to sequences with UG repeats and UGUU motifs. It also binds to the 3'-UTR of cyclooxygenase-2 messages, affecting both translation and mRNA stability, and binds to apoB mRNA, regulating its C to U editing []. CELF-2 also contains three highly conserved RRMs. It binds to RNA via the first two RRMs, which are also important for localization in the cytoplasm. The splicing activation or repression activity of CELF-2 on some specific substrates is mediated by RRM1/RRM2. Both, RRM1 and RRM2 of CELF-2, can activate cardiac troponin T (cTNT) exon 5 inclusion. In addition, CELF-2 possesses a typical arginine and lysine-rich nuclear localization signal (NLS) in the C terminus, within RRM3 [].
Protein Domain
Type: Domain
Description: The human CELF family has six members, which can be divided into two subfamilies based on their phylogeny: CELF1-2 and CELF3-6. This entry represents the RNA recognition motif 1 (RRM1) of CELF-1 and CELF-2 protein. CELF-1 and CELF-2 belong to the CELF (CUGBP and ETR-3 Like Factor)/Bruno-like protein family, whose members play important roles in the regulation of alternative splicing and translation. CELF-1 and CELF-2 share sequence similarity to the Drosophila Bruno protein and binds to the Bruno response elements (cis-acting sequences in the 3'-untranslated region (UTR) ofoskar mRNA) [].The human CELF-1 (also known as CUG-BP or BRUNOL-2) binds to RNA substrates and recruits PARN deadenylase []. It preferentially targets UGU-rich mRNA elements []. CELF-1 has been implicated in onset of type 1 myotonic dystrophy (DM1), a neuromuscular disease associated with an unstable CUG triplet expansion in the 3'-UTR (3'-untranslated region) of the DMPK (myotonic dystrophy protein kinase) gene [, ]. CELF-1 contain three highly conserved RNA recognition motifs (RRMs): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C terminus of the protein. The Xenopus homologue of CELF-1 is EDEN-BP (embryo deadenylation element-binding protein), which mediates sequence-specific deadenylation of Eg5 mRNA. It binds specifically to the EDEN motif in the 3'-untranslated regions of maternal mRNAs and targets these mRNAs for deadenylation and translational repression []. The two N-terminal RRMs of EDEN-BP are necessary for the interaction with EDEN as well as a part of the linker region (between RRM2 and RRM3). Oligomerization of EDEN-BP is required for specific mRNA deadenylation and binding []. CELF-2 (also known as CUGBP2 or ETR-3) shares high sequence identity with CELF-1, but shows different binding specificity; it binds preferentially to sequences with UG repeats and UGUU motifs. It also binds to the 3'-UTR of cyclooxygenase-2 messages, affecting both translation and mRNA stability, and binds to apoB mRNA, regulating its C to U editing []. CELF-2 also contains three highly conserved RRMs. It binds to RNA via the first two RRMs, which are also important for localization in the cytoplasm. The splicing activation or repression activity of CELF-2 on some specific substrates is mediated by RRM1/RRM2. Both, RRM1 and RRM2 of CELF-2, can activate cardiac troponin T (cTNT) exon 5 inclusion. In addition, CELF-2 possesses a typical arginine and lysine-rich nuclear localization signal (NLS) in the C terminus, within RRM3 [].Proteins containing this motif also include Drosophila melanogaster Bruno protein, which plays a central role in regulation ofOskar (Osk) expression in flies. It mediates repression by binding to regulatory Bruno response elements (BREs) in the Osk mRNA 3' UTR []. The full-length Bruno protein contains three RRMs, two located in the N-terminal half of the protein and the third near the C terminus, separated by a linker region.