Marc Vasseur

Sequence of a cDNA encoding human keratin No 10 selected according to structural homologies of keratins and their tissue-specific expression.

We present here the nucleotide sequence of a 1700 bp-long cDNA encoding human epidermal keratin No. 10 (56.5 kDa). cDNA clones of the acidic keratin family were first isolated from a pBR322 human epidermal cDNA library by hybridization with a probe coding for keratin No. 14. Differential hybridization using total cDNA probes prepared from poly(A)+ RNA extracted either from epidermis (which contains keratin No. 10) and from squamous carcinoma or hepatoma cell lines (which do not express keratin No. 10) made possible the selection of clones potentially coding for keratin No. 10. The 1.7 kb sequence exhibits the characteristic features of an acidic keratin with a constant central rod domain and C-terminal variable structures. Moreover, the sequence shows extensive homologies with the cDNA of murine keratin No. 10.

Synthesis and properties of DNA dumbbells containing chemically active substituted pyrophosphate internucleotide groups

Abstract DNA dumbbells with substituted pyrophosphate groups at a definite position of the sugar-phosphate backbone were synthesized by condensation of terminal 5′-phosphomonester- and 3′-methylphosphodiester groups in nicked dumbbells. N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide was used as a condensing agent. An efficient method for producing extended oligonucleotides carrying an O-methyl-substitued 3′-phosphate group was developed. Properties of the modified DNA-dumbbells were investigated. The substituted pyrophosphate group in the DNA dumbbells was efficiently cleaved under the action of N-methylimidazole or ethylendiamine aqueous solutions at pH 8.0.