Methods of identifying modulators of TDP-43 mediated cellular toxicity

1. A method of inhibiting TDP-43 mediated cellular toxicity, the method comprising contacting a cell comprising a genetic construct for expressing a toxicity inducing amount of a C-terminal variant of TDP-43 consisting of amino acids 188 to 414 of SEQ ID NO: 1, with an effective amount of an agent that inhibits expression or activity of at least one gene selected from the group consisting of DBR1, PCL6, SAK1, YCK2, MEC1, UBP7, RGA2, KEL1, DIP5, ROM2, VHS1, YHR131C, SLF1, HRP1, PBP1, KEM1, MSN5, SRO9, SFG1, MSA1, PIB2, SLG1, MTH1, CDC6, TSC11, SOL1, KIN3, PBP2, SET3, CCE1, SIW14, YDR067C, DOM34, MGD1, RPL16, and human homologs thereof, or an agent that increases expression or activity of at least one gene selected from the group consisting of FMP48, VTS1, XRS2, HSP104, TIS11, BFR1, ICS2, YKL171W, PGM1, ADY3, RIM15, CYC8, RDR1, TIF4631, MRPL39, FLD1, MSN2, PBL16B, NHX1 and human homologs thereof, wherein when said gene is to be inhibited said agent is an antisense, ribozyme or siRNA complementary to mRNA transcribed from said gene such that it binds said mRNA under physiological conditions, and inhibits its translation and wherein when said expression of said gene is to be increased, a vector encoding a polypeptide encoded by said gene is introduced into said cell.

2. The method of claim 1 , wherein said gene is DBR1, and said agent is an siRNA comprising a guide strand complementary to DBR1 mRNA which specifically inhibits expression of DBR1.

3. A method for identifying agents which inhibit TDP-43 mediated cellular toxicity, comprising:

a) providing a cell which comprises a genetic construct for expressing a C-terminal TDP-43 variant consisting of amino acids 188-414 of SEQ ID NO: 1, said expression being associated with increased protein aggregation and cellular toxicity as compared to cells which lack said variant;

b) contacting said cell with an effective amount of an agent which inhibits expression or activity of at least one gene selected from the group consisting of

i) PCL6, SAK1, YCK2, MEC1, UBP7, RGA2, KEL1, DIPS, ROM2, VHS1, YHR131C, SLF1, HRP1, PBP1, KEM1, MSN5, SRO9, SFG1, MSA1, PIB2, SLG1, MTH1, CDC6, TSC11, SOL1, KIN3, PBP2, SET3, DBR1, CCE1, SIW14, YDR067C, DOM34, MGD1, RPL16, and human homologs thereof

ii) an agent which increases expression or activity of at least one gene selected from the group consisting of FMP48, VTS1, XRS2, HSP104, TIS11, BFR1, ICS2, YKL171W, PGM1, ADY3, RIM15, CYC8, RDR1, TIF4631, MRPL39, FLD1, MSN2, PBL16B, NHX1 and human homologs thereof; and

c) measuring cellular toxicity in the presence of said agent relative to a non-treated control, wherein a decrease in cellular toxicity identifies an agent which reduces TDP-43 mediated cellular toxicity, wherein when said gene is to be inhibited said agent is an antisense, ribozyme or siRNA complementary to mRNA transcribed from said gene such that it binds said mRNA under physiological conditions, and inhibits its translation and wherein when said expression of said gene is to be increased, a vector encoding a polypeptide encoded by said gene is introduced into said cell.

4. The method of claim 3 , comprising assessing the effects of said agent on TDP-43 mediated protein aggregation.

5. A transgenic yeast cell comprising,

i) a genetic construct which, upon expression, produces a C terminal variant TDP-43 protein consisting of amino acids 188 to 414 of SEQ ID NO 1, said yeast cell further comprising

ii) a nucleic acid construct encoding a TDP-43 activity modifier, said modifier altering TDP-43 toxicity when over expressed, said modifier being selected from the group of modifiers consisting of DBR1, PCL6, SAK1, YCK2, MEC1, UBP7, RGA2, KEL1, DIP5, ROM2, VHS1, YHR131C, SLF1, HRP1, PBP1, KEM1, MSN5, SRO9, SFG1, MSA1, PIB2, SLG1, MTH1, CDC6, TSC11, SOL1, KIN3, PBP2, SET3, CCE1, SIW14, YDR067C, DOM34, MGD1, RPL16, FMP48, VTS1, XRS2, HSP104, TIS11, BFR1, ICS2, YKL171W, PGM1, ADY3, RIM15, CYC8, RDR1, TIF4631, MRPL39, FLD1, MSN2, PBL16B, and NHX1, wherein said nucleic acid construct is heterologous to said yeast cell.

6. The yeast cell of claim 5 , wherein over-expression of said modifier reduces TDP-43 cytotoxicity.

7. The yeast cell of claim 5 , wherein over-expression of said modifier enhances TDP-43 mediated cytotoxicity.

8. The yeast cell of claim 5 , wherein at least one of said constructs comprises an inducible promoter.

9. The method of claim 1 , wherein said agent is an antisense, ribozyme or siRNA complementary to DBR1 mRNA such that it binds said DBR1 mRNA under physiological conditions, and inhibits its translation.