Cystic FibrosisFrom Gene to

ProteinClass instructions

In this lesson

• Look at the normal and mutated CFTR gene

• Make messenger RNA (mRNA) from DNA- transcription

• Make protein from mRNA- translation

The devil is in the detail!

• The 5’ prime and 3’ prime ends of the bases must be round the right way!

IMPORTANT: Do not take

bases apart!!!

Correct base pairing is critical!

• Green (Guanine) pairs with yellow (Cytosine)

• Blue (Adenine) pairs with orange (Thymine)

Lesson – part 1Normal CFTR Gene ΔF508 CF Mutation

Sense

Antisense

Sense

Antisense

Transcription – Step 1

Base pairing in mRNA- use brown sugars

• Green (Guanine) pairs with yellow (Cytosine)

• Blue (Adenine) pairs with light blue (Uracil)

Transcription – Step 2• To make an mRNA, you must use the

antisense (red sugars) strand as as the template as base pairing is complimentary.

Resulting mRNA

Normal CFTR mRNA ΔF508 CFTR mRNA

Translation

• Turns mRNA into protein• Use transfer RNA (tRNA) which are

attached to amino acids as intermediate

• Amino acids have a direction too!

N-terminal C-terminal

Transfer RNA

UAAIsoleucine

CAAValine

CCAGlycine

AAAPhenylalanine

UAAIsoleucine

tRNA – holds an anticodon at one end, and an amino acid at the other

Using mRNA in 5’-3’ orientation, translate into

protein.

Separate tRNA & protein from mRNA

Resulting protein

Isoleucine – Phenylalanine - Glycine

Isoleucine – Glycine - Valine

Normal CFTR protein

ΔF508 CFTR protein

Polymerase Chain Reaction

• Using the original chromosomes, separate strands

• Find where primers stick to each strand

Genetic Test • Using the original chromosomes, see what a PCR

product will look like.• Remember: Each individual will have 2 chromosomes

- one inherited from mother and one from father.

DNA gel genetic test result