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]: This enhancer element functioned in a position - and orientation - independent manner both on the Pax - QNR P0 promoter and the heterologous thymidine kinase promoter .
[A]: thymidine kinase

[Q]: Recently we have performed a detailed analysis of specific neuronal populations affected by the mutation which shed new light on the role of Krox - 20 in the segmentation and on the physiological consequences of its inactivation .
[A]: Krox - 20

[Q]: Searching the human DNA data base of expressed sequence tags ( EST ) revealed novel partial sequences similar to , but distinct from , the sequences of the previously known PEF proteins .
[A]:
PEF proteins