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1.. Intragenic repeats generate size variability in immunogenic proteins in Aspergillus fumigatus Nir Osherov Human Microbiology Department, Tel Aviv.

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Presentation on theme: "1.. Intragenic repeats generate size variability in immunogenic proteins in Aspergillus fumigatus Nir Osherov Human Microbiology Department, Tel Aviv."— Presentation transcript:

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2 Intragenic repeats generate size variability in immunogenic proteins in Aspergillus fumigatus Nir Osherov Human Microbiology Department, Tel Aviv University 2.

3 What is repetitive DNA? Three types: Satellite 100Kb-1Mb Centromere Microsatellite <150b Variable locations Coding Non-coding Minisatellite1Kb-20KbTelomere 3.

4 Example of tandem repeat containing protein DNA Afu2g5150 Protein Variable protein 4.

5 S.cerevisiae FLO1 adhesin leaderGPI-anchor motif N--C Ser/Thr-rich Tandem- repeats 5.

6 What is the effect of tandem repeat elongation on adhesion? FLO1 is a GPI-anchored tandem-repeat protein involved in adhesion in S. cerevisiae Adhesion increases…. Flocculation increases… Verstrepen et al., Nature Genetics 2005 As the number of repeats increases… 6.

7 Does variability exist in the population? Different S. cerevisiae strains carry FLO1 alleles of varying lengths S. cerevisiae strain 7. Verstrepen et al. Nature Genetics 2005

8 Aims of research Are there tandem repeats in A.fumigatus genes and are they size-variable? Are there tandem repeats in A.fumigatus genes and are they size-variable? Are there tandem repeat-containing CWPs in A.fumigatus and are they size-variable? Are there tandem repeat-containing CWPs in A.fumigatus and are they size-variable? How will their deletion affect the phenotype? How will their deletion affect the phenotype? 8

9 Tandem repeats – A. fumigatus Kevin Verstrepen, Gerry Fink, MIT 292 ORFs containing Tandem Repeats (Etand>35) Tandem repeats ETANDEM A. fumigatus annotated genome 9.

10 How does the data look? Afu3g Afu2g Afu4g09600 Conservation % Rpt # Rp t size Etandem score Rpt end Rpt start Gene name 10.

11 Are these tandem-repeat (TR) genes variable in size among A. fumigatus isolates? Aspergillus isolates Genomic DNA PCR TR-gene Aspergillus isolate # 11.

12 Summary 12.

13 Af bp Afu3g08990 Score= bp 1001 bp Afu6g14090 CFEM Score= bp Afu2g05150 (MP-2) Score=301 Afu4g09600 Score=292 Strain: A.fumigatus GPI anchored genes with high ETANDEM scores have size-variable repeats 13.

14 Top-scoring A. fumigatus GPI- anchoredTR genes transcribe size-variable mRNA 14.

15 GPI-anchored TR genes encode for discrete numbers of in-frame repeats 15. Cons. Hypoth. CFEM Cons. Hypoth. MP-2 immunogenic secreted. Cons. Hypoth.

16 Top scoring GPI & leader- containing genes at different time points Δ Δ Δ 16.

17 Afu3g08990 in silico analysis (~PGQPSV)18-32 six aa C-terminal rpts Extended rod domain of collagen P/T/S rich N-terminal region 17.

18 tBlastN fungal E-value gb|AAHF | Aspergillus fumigatus 00. ref|NZ_AAKE | Neosartorya fischeri 9e-26 ref|NZ_AAKD | Aspergillus clavatus 6e-09 gb|AACD | Aspergillus nidulans 3e-06 gb|AAJN | Aspergillus terreus 8e-04 gb|AAIH | Aspergillus flavus 8e-04 ref|NZ_AAFU | Chaetomium globosum ref|NC_ | Ashbya gossypii gb|AAEG | Saccharomyces cerevisiae Afu3g08990-like genes are Aspergillus-specific and extremely divergent 18.

19 A. fumigatus Afu3g08990 Neosartorya fischeri 9e-26 Aspergillus clavatus 6e-09 Aspergillus nidulans 3e-06 Aspergillus terreus 8e

20 Lactobacillus hyp aa 1369 aaTetrahymena FH aaStrep. agalactiae C-protein β-ag 940 aaTryp. cruzi trans-sialidase aaAfu3g08990 TR region 954 aa Human collagen type XXI Pan-species Blast reveals little…. 20.

21 Afu3g08990 expression is upregulated by damage to the cell wall and plasma membrane 21.

22 3 1 2 random AF 293 KI Time (h) Hyphal length in µm Deletion of Afu3g08990 leads to early germination 22.

23 AF random KI Conidia per field The Afu3g08990 strains exhibit reduced adhesion to ECM 23.

24 Afu3g08990 repeat region can be used for strain typing Balajee et al. 2007, submitted.

25 Summary Afu3g08990 Transcribed during germination and vegetative growth Upregulated by cell-wall stress ΔAfu3g08990 conidia germinate faster than WT ΔAfu3g08990 conidia show reduced adherence to ECM ΔAfu3g08990 mutant NOT more susceptible to CAS, CR, CFW No change in virulence (mouse tail vein model) 24.

26 What does Afu3g08990 do? 1. Receptor? 2. Cross-linker cement ? 25. PM 3. Reservoir model

27 Yana Shadkchan Emma LevdanskyHaim SharonKobi Romano 26. Kevin Verstrepen, Harvard Gerry Fink, Whitehead Inst. Collaborators:

28 Thank you ! 28.


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