We report the complete thermodynamic library of all 10 Watson-Crick DNA nearest-neighbor interactions. We obtained the relevant thermodynamic data from calorimetric studies on 19 DNA oligomers and 9 DNA polymers. We show how these thermodynamic data can be used to calculate the stability and predict the temperature-dependent behavior of any DNA duplex structure from knowledge of its base sequence. We illustrate our method of calculation by using the nearest-neighbor data to predict transition enthalpies and free energies for a series of DNA oligomers. These predicted values are in excellent agreement with the corresponding values determined experimentally. This agreement demonstrates that a DNA duplex structure thermodynamically can be considered to be the sum of its nearest-neighbor interactions. Armed with this knowledge and the nearest-neighbor thermodynamic data reported here, scientists now will be able to predict the stability (AG') and the melting behavior (AW) of any DNA duplex structure from inspection of its primary sequence. This capability should prove valuable in numerous applications, such as (i) predicting the stability of a probe-gene complex; (ii) selecting optimal conditions for a hybridization experiment; (iii) deciding on the minimum length of a probe; (iv) predicting the influence of a specific transversion or transition on the stability of an affected DNA region; and (v) predicting the relative stabilities of local domains within a DNA duplex.It is well established that under a given set of solution conditions the relative stability of a DNA duplex structure depends on its base sequence (1-4). More specifically, the stability of a DNA duplex appears to depend primarily on the identity of the nearest-neighbor bases. Ten different nearestneighbor interactions are possible in any Watson-Crick DNA duplex structure. These pairwise interactions are AA/TT; AT/TA; TA/AT; CA/GT; GT/CA; CT/GA; GA/CT; CG/GC; GC/CG; GG/CC. The overall stability and the melting behavior of any DNA duplex structure can be predicted from its primary sequence if one knows the relative stability (AG') and the temperature-dependent behavior (Al?, ACp°) of each DNA nearest-neighbor interaction (5, 6).Tinoco and coworkers already have demonstrated the power of this predictive ability with RNA molecules for which they and others have determined the appropriate thermodynamic data (7-11). Unfortunately, comparatively few corresponding studies on DNA oligomers have been performed so that the relevant thermodynamic data required to predict DNA structural stability are rather sparse. The seriousness of this deficiency is dramatized by the fact that investigators attempting to evaluate sequence-dependent structural preferences in DNA molecules have resorted to the use of the more available RNA thermodynamic data. This use of RNA data does not reflect a belief that DNA and RNA are thermodynamically equivalent but rather is born of necessity due to a lack of the relevant DNA thermodynamic data. In fact, available comparisons su...

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Normal as well as retrovirally transformed avian myeloid precursor cells require the colony stimulating factor cMGF for their survival, proliferation and colony formation in vitro. cMGF has been shown to be a glycoprotein which is active in the picomolar concentration range. Co‐expression of kinase type oncogenes in v‐myb or v‐myc transformed myeloid cells induces cMGF expression and confers factor independence via an autocrine mechanism. Here we describe the molecular cloning of cMGF from a myeloblast cDNA library and show that it is a 201 amino acid residue secretory protein which is modified by signal peptide cleavage and glycosylation during translocation into the lumen of membrane vesicles. A bacterially expressed trpE‐cMGF fusion protein induces proliferation of E26 transformed myeloblasts in a cMGF bioassay suggesting that glycosylation is not absolutely necessary for biological activity. Sequence comparison reveals that cMGF is distantly related to G‐CSF and IL‐6.