sentence: Sequences encoding selected regions of cyclins ( amino acid residues 1 – 243 of CYCA1 ; 1 , 1 – 206 of CYCB1 ;3 , 263 – 358 of CYCD2 ; 1 and 243 – 349 of CYCD5 ; 1 ) and full-length CDKA ; 1 and CDKB1 ; 1 were amplified from cDNA clones with Pfu DNA polymerase ( Stratagene , San Diego , CA , USA ) .