Question

You have discovered a new protein, named L8 that may contribute to transformation of normal lung cells into cancerous lung cells. To determine the mechanism by which this protein is contributing to the transformed phenotype you generate genetically-mutated mice that are lacking one copy of the gene encoding L8 (L8+/L8-), both copies of the gene encoding L8 (L8-/L8-), or are expressing abnormally high levels of the L8 protein (L8hi/L8hi). You track the formation of lung tumors in these mice compared to normal mice (L8+/L8+). The L8 protein is likely a:

The results are shown in Figure A.

Figure A

A) Oncoprotein

B)	Additional information is required to determine the nature of L8

C)	Tumor suppressor protein

Answer 1

The L8 is a tumor suppressor protein. In the figure A the number of tumors increased when both the alleles of genes were absent in the mutated mice. These results showed that in the presence of L8 protein the tumor was suppressed in all three conditions when gene was present and in absence of L8 protein the lung cells were continuously transformed into tumor cells. Suggesting that single copy of gene was enough to suppress the tumor and is contributing for the transformation of lung cells into tumor cell in negative sense, by suppressing tumor transformation.

The question also needs further information for the role of L8hi