was used in run 4 an amino acid sequence analysis wherein the protein sample was applied to a tfa activated glass fiber disc without polybrene sequence analysis was carried out with an ab 470a sequencer according to the methods of hewick et al j biol chem 256 7990 7997 1981 and lai anal chim acta 163 243 248 1984 the results of run 4 appear in table iii table iii__________________________________________________________________________1 5 10 pro 15 20 glu glu 25 30 ala gly x__________________________________________________________________________ in run 4 beyond 31 cycles corresponding to residue 31 in table iii no further significant sequence information was obtained in order to obtain a longer unambiguous sequence in a run 5 14 u03bcg of hpg csf purified from conditioned medium were reduced with 10 u03bcl of u03b2 mercaptoethanol for one hour at 45 u00b0 c then thoroughly dried under a vacuum the protein residue was then redissolved in 5 formic acid before being applied to a polybrenized glass fiber disc sequence analysis was carried out as for run 4 above the results of run 5 are given in table iv table iv__________________________________________________________________________1 5 10 pro 15 20 gln 25 30 ala 35 40 lys 45x met __________________________________________________________________________ the amino acid sequence given in table iv was sufficiently long 44 residues and unambiguous to construct probes for obtaining hpg csf cdna as described infra among standard procedures for isolating cdna sequences of interest is the preparation of plasmid borne cdna 34 libraries 34 derived from reverse transcription of mrna abundant in donor cells selected on the basis of their expression of a.