High impact information on CLF1

• Here we report that Crooked neck (Crn), the Drosophila homolog of the yeast Clf1p splicing factor, is directing peripheral glial cell maturation [1].
• The structure of Prp40 FF1 domain and its interaction with the crn-TPR1 motif of Clf1 gives a new insight into the binding mode of FF domains [2].
• By using chemical shift assays, we found a binding site for the N-terminal crooked neck tetratricopeptide repeat of Clf1 that is distinct and structurally separate from the previously identified CTD-RNAPII binding pocket of the FBP11 (formin-binding protein 11) FF1 domain [2].
• The Clf1p splicing factor promotes spliceosome assembly through N-terminal tetratricopeptide repeat contacts [3].
• In a two-hybrid analysis with Csm1p as bait, we detected interactions with three members of the Mcm2-7 family of proteins involved in the initiation of DNA replication, and with Clf1p also implicated in replication [4].

Biological context of CLF1

• CLF1 is an essential gene but the lethal phenotype of a clf1::HIS3 chromosomal null mutant can be rescued by plasmid-based expression of CLF1 or the Drosophila crn open reading frame [5].
• In addition we show that depletion of Syf1p or Syf3p results in cell cycle arrest at the G2/M transition [6].
• We isolated temperature-sensitive clf1 mutants that exhibit similar mitotic defects when released to the restrictive temperature from an early S-phase block [7].

Anatomical context of CLF1

• Clf1 is a conserved spliceosome assembly factor composed predominately of TPR repeats [8].

Other interactions of CLF1

• Syf1p and Syf3p are highly conserved proteins containing several copies of a repeated motif, which we term RTPR [9].
• This delay could not be suppressed by disruption of the S-phase CDK inhibitor SIC1, suggesting that Clf1p is involved in DNA replication [7].
• We have now identified three other components of the complex, Ntc90p, Ntc77p and Ntc31p [10].

References