TASK DEFINITION: In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.
PROBLEM:  Molecular cloning of cDNAs encoding alpha - subunits of guanine nucleotide - binding regulatory proteins ( G - proteins ) has revealed the existence of nine species of alpha - subunits .

SOLUTION: G - proteins

PROBLEM:  PCC 6803 mutant impaired in cytochrome c maturation .

SOLUTION: cytochrome c

PROBLEM:  We conclude from these observations that the cTnC 3 ' Ile element is a composite enhancer that functions through the combined interactions of at least five regulatory elements and their cognate binding factors : three or four E - boxes , a MEF - 2 site , and a MEF - 3 site .

SOLUTION:
MEF - 2