Molecular cloning of 5'-regulatory region of bovine alpha S1-casein gene.

A DNA fragment of bovine alpha S1-casein gene was obtained from bovine genomic library using bovine alpha S1-casein cDNA as a probe. Restriction endonuclease map and Southern blot analysis suggest that it contains the complete 5'-regulatory region of bovine alpha S1-casein gene.

HsaI: a restriction enzyme from human being.

The HsaI restriction enzyme from the embryos of human, Homo sapiens, has been isolated with both the tissue extract and nuclear extract. It proves to be an unusual enzyme, clearly related functionally to Type II endonuclease. HsaI seems to be an isoschizomer of EcoRI, but it has a distinctive property of elution, differing from EcoRI.

Constructions of gene libraries of Rana nigromaculata and Mus musculus with cosmid pHC79.

Gene libraries of Rana nigromaculata and Mus musculus (C57J6) have been constructed by the cosmid system developed by Collins using BamHl and Pstl as cloning restriction enzymes. A simplified formula, which is a modification of Clarke and Carbon derived from approximation, was used for calculating the number of colonies or recombinants necessary for the construction of a gene library. Pro+ and leu+ complementary to the recipient cells (HB101) with the genetic constitution of pro- and leu- have been selected from the BamH1 gene libraries of both Rana nigromaculata and the mouse in the present work.