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.

[Q]:  Functional characterization of the two alternative promoters of human p45 NF - E2 gene .
[A]: alternative promoters


[Q]:  The number of binding sites was not significantly modified .
[A]: binding sites


[Q]:  In an effort to understand the physiologic consequences of BAP / TFII - I tyrosine phosphorylation following B cell receptor stimulation , site - directed mutagenesis and phosphopeptide mapping were used to locate the predominant sites of BAP / TFII - I phosphorylation by Btk in vitro .
[A]:
B cell receptor