Restriction endonucleases are :

Restriction endonucleases are synthesized by bacteria as part of their defense mechanism. In the year 1963, the two enzymes responsible for restricting growth of bacteriophages in Escherichia coli were isolated. One of these added methyl groups to host DNA, while the other cut DNA. The later was called restriction endonulease.

For in vitro synthesis of DNA, we have to use a type of DNA polymerase. 

For ligation of two DNA molecules enzyme DNA ligase is required.