-ribosomes are subject to K and R methylation. -Rmt2 modifies R's. The physiological role of R-met is unknown.Thought to mediate ribosome RNA interactions. -Rkm1/2 methylate K's. This is the non-histone methylating branch of SET proteins. Family has 3 members. -in mammals it's believed that these modificaitons play a role in the cell cycle. -polysome analysis revealed no difference b/w WT and rkm2KO cells.

CARM1 enhances transcription activation my nuclear receptors by interacting w. coactivators p160 and CBP and methylates H3R17. -CARM1 also acts as coactivator for nuclear TF NFkappaB in 293T. -CARM1 is recruited to NFkappaB promoters, accompanied by increase in H3R17met and H3K9,14-Ac. -This is a non-nuclear receptor associated function for CARM1. ie it works with p300 (CBP) instead of p160 dependent transcription for nuclear receptor mediated transc.

Cellular processes regulated by R-met: RNA processing- most RNA binding proteins are methylated. Key R's exist w/in active sites and therefore R-met might negatively affect binding. Alternatively as R-met is more hydrophobic and therefore may facilitate stacking w. RNA bases. Transcriptional regulation- TFs (p53, NFKappaB) recruit PRMTs to promoters. PRMTs methylate both histones and coactivators (CPB/p300) and elongation factors (SPT5). Signal transduction- protein-protein interactions via Sh3 are R-met sensitive. Involved in T cell receptor pathways. DNA repair- PRMT1 methylates Mre11 at GAR motif. regulates exonuclease enxymatic activity. PMRT1 RNAi shows checkpoint defects in response to DNA damage -propose that amide oxidases could remove R-met and make formamide in similar mechanism as lysine HMTs. type 1 and type 2 PRMT enxymes can act on the same R reside. ie. PRMT1 and PRMT5 may act on same residue. May antagonise eachother and differentially regulate function. R-met and cancer- small molecule that inhibit both PRMT1 and CARM1 and suppress estrogen and endrogen receptor mediated transc. activation. Increased CARM1 expression correlates with androgen independence in human carcinoma. -PRMTs recognize GAR consensus.

Nuclear receptors- turn on gene transcription by recruiting. HNF4 binds genes necessary for development. Shows that PRMIT is a coactivator that regulates HNF4 DNA-binding activity and methylates H4R3 which acts synergistically with other HNF4 coactivators. -first PRMIT binds HNF4 and emthylates its DNA bindign domain which enhances its affinity for it's binding site. -Second PRMIT is recruited to the HNF4 ligand binding domain in a coactivator dependnet manner and methylates H4R3. Works w. recruitment of p300 HAT to activate transcription. -In vitro transcription- incubate recombinant chromatin w. factors of interest and HeLa nuclear extract for PIC formation. Add labeled nucleotides and visualize by autoradiography. -showed there was a synergy between PRMIT and other coactivators to get transcription. -used in vitro ChIP to test recruitment of activators to promoter w. 700-bp probe.

PADI4 deiminates H3R2,8,17 unmethylated and monomethylated. H3 arg methylation is linked with transc activation at pS2 (estrogen regulated promoter) in 293 cells. CARM1 methyltransferase methylates these residues to activate transcription. PADI4 activity represses hormone-receptor mediated gene induction. PADI4 is recruited to pS2 following hormone inducation when transcription is down regulated. -show in vitro deimination w. anti-citrulline. -also generated an antibody specific for H3 dimination. -targeted PADI4 to hormone receptor regulated promoter is sufficient to repress hormone dependent transcriptional activation. Similar results have been shown when targeting Suvh39 and G9a to the same promoter. -PADI4 and subsequent R deimination occur at pS2 promoter in response to estrogen. Subsequent loss of RNA pol at promoter.

H4R3-me leads to subsequent Ac of H4 tails for p300. H4-Ac inhibits H4R3-methyl. PRMT1 SAM binding site mutants lead to defects in nuclear receptor coactivator activity. -methyl transferase was identified by fractionating cells and determining which fraction cotnains PMRT activity.

Hmt1 (also calle RMT1) is PRMT for H3K4. hmt1KO- increased transcripion in silent TEL region (ADE2 construct) -increase mitotic recomb in rDNA repeats-> half sectoring, loss of ADE2 inserted in repeats. R-met of other proteins: methylation of Src kinase substrate controls its ability to interact w. SH3 proteins. -methylation of Spt5 regulates its ability to interact w. PolII which is crucial for transcription. PAD4- converts monomethyl R into cirtulline. Showed Hmt1 is necessary for Sir2 recruitment at HM and TEL. -see increase in H4-acetyl at HM and TEl in hmtiKO -dont test H4K3R mutant. But do show HMt1 leads to H4K3-methyl in subtel and HM. Hmt1 ChIP-chip show it localizes to stress genes

Hsl7 (histone synthetic lethal 7) shows sequence similarity to mammalian PRMT5. Purified Hsl7 incorporates 3H-SAM into bovine H2A.Did not act on purified yeast histones. Rmt1 (known yeast PRMT) also methylated cow H2A.