1. Purposes:
To demonstrate the tendency of proteins to become longer with increase of organism complexity
To study domain architecture of proteins and to date different domains

2. Homologous proteins Orthologs Paralogs
Have evolved by vertical descent from a common ancestor and are presumed to have complete structural and functional correspondence
Arise by duplication and domain shuffling within a genome and hence may have divergent functions
New function
We are interested in proteins that have changed their domain content, but preserved the same function

5. Human HRX protein
PHD
zf-CXXC
SET
FYRN
FYRC
BROMO

6. Plant PHD SET BROMO zf-CXXC FYRC FYRN zf-C4 RRM PostSET HMG PWWP TUDOR
gi| |gb|AAK |AF401284_1 trithorax 3 [Arabidopsis thaliana] (330 letters)
gi| |ref|NP_ | putative protein [Arabidopsis thaliana] (902 letters)
gi| |gb|AAF |AC009999_10 Contains similarity to MLL
proteinfrom Fugu rubripes gb|AF036382, and contains a PWWP PF|00855
and a SET PF|00856 domain. [Arabidopsis thaliana] (1193 letters)
gi| |ref|NP_ | putative SET-domain transcriptional regulator [Arabidopsis thaliana] (186 letters)
gi| |ref|NP_ | putative protein [Arabidopsis thaliana] (1040 letters)
gi| |gb|AAL | trithorax 4 [Arabidopsis thaliana] (285 letters)
gi| |ref|NP_ | putative protein [Arabidopsis thaliana] (1421 letters)
gi| |ref|NP_ | unknown protein [Arabidopsis thaliana] (764 letters)

7. Yeast Worm PHD SET BROMO zf-CXXC FYRC FYRN zf-C4 RRM PostSET HMG PWWP
TUDOR
gi| |pir||T41282 probable transcription silencing protein - fission yeast
(Schizosaccharomyces pombe) (920 letters)
gi| |ref|NP_ | Gene has a 'SET' or 'TROMO' domain at its carboxyterminus like the
trithorax gene family from human and Drosophila with postulated function in chromatin-mediated
gene regulation.; Set1p [Saccharomyces cerevisiae] (1080 letters)
Yeast
Worm
gi| |ref|NP_ | C26E6.9a.p [Caenorhabditis elegans] (1507 letters) +
gi| |ref|NP_ | C26E6.9b.p [Caenorhabditis elegans] (739 letters)
gi| |ref|NP_ | PHD-finger. (2 domains), SET domain
[Caenorhabditis elegans] (2561 letters)

8. Fly PHD SET BROMO zf-CXXC FYRC FYRN zf-C4 RRM PostSET HMG PWWP TUDOR
gi| |gb|AAL | GM10003p [Drosophila melanogaster] (421 letters)
gi| |pir||T12687 ALR protein homolog - fruit fly (Drosophila melanogaster) (2422 letters)
gi| |gb|AAF | CG17396 gene product [Drosophila melanogaster] (177 letters)
gi|469801|emb|CAA | predicted trithorax protein
[Drosophila melanogaster] (3358 letters)
gi| |gb|AAF | CG5591 gene product [Drosophila melanogaster] (630 letters)
gi| |gb|AAK | LD39445p [Drosophila melanogaster] (700 letters)
gi| |sp|Q24742|TRX_DROVI Trithorax protein (3828 letters)

9. Human PHD SET BROMO zf-CXXC FYRC FYRN zf-C4 RRM PostSET HMG PWWP TUDOR
gi| |sp|Q03164|HRX_HUMAN Zinc finger protein HRX
(ALL-1) (Trithorax-like protein) (3969 letters)
gi| |gb|AAD | myeloid/lymphoid leukemia 2 [Homo sapiens] (1010 letters)
gi| |dbj|BAA | KIAA0304 protein [Homo sapiens] (1900 letters)
gi| |gb|AAH |AAH09337 Similar to KIAA0304 gene product
[Homo sapiens] (798 letters)
gi| |gb|AAH |AAH07353 Similar to KIAA0304 gene product [Homo sapiens] (140 letters)
gi| |gb|AAD |AF105280_1 myeloid/lymphoid leukemia 2 [Homo sapiens] (140 letters)

10. Human - continued PHD SET BROMO zf-CXXC FYRC FYRN zf-C4 RRM PostSET
HMG
PWWP
TUDOR
Human - continued
gi| |ref|NP_ | mixed-lineage leukemia 2;
ALL1-related gene [Homo sapiens] (5262 letters)
gi| |pir||T03455 ALR protein - human (4957 letters)
gi| |dbj|BAA | KIAA0339 protein [Homo sapiens] (1709 letters)
gi| |ref|XP_ | KIAA1076 protein [Homo sapiens] (772 letters)
gi| |ref|NP_ | mixed-lineage leukemia 3;
ALR-like protein [Homo sapiens] (4025 letters)
gi| |dbj|BAB | unnamed protein product [Homo sapiens] (452 letters)

11. 940Ma 1087Ma 1508Ma Protista PHD SET BROMO zf-CXXC FYRC FYRN zf-C4 RRM
PostSET
HMG
PWWP
TUDOR
Vertebrates
Homo sapiens
940Ma
Arthropods
Drosophyla melanogaster
Drosophyla virilis
1087Ma
Nematodes
Caenorhabditis elegans
Fungi
Schizosaccharomyces pombe
Saccharomyces cerevisiae
1508Ma
Protista
Plants
Arabidopsis thaliana

12. Conclusion:
Elongation of proteins within interspecific trx family is correlated with organism complexity
Proteins elongate following domain duplication, shuffling and accretion