GO Tutorial: Annotating A Paper

Exercise IV

Annotation - Answers

Thanks to Emily Dimmer for providing the annotations!

Page 13919, first paragraph

Few coactivators show tissue-specific expression. One of them is PGC-1, which
is expressed at high levels in tissues such as heart, skeletal muscle, kidney,
and brown fat. PGC-1 expression is induced also in a tissue-specific manner, in
response to particular physiological states such as exposure to cold or fasting.
Induction of PGC-1 in response to signals indicating metabolic needs of an
organism can then lead to the activation of pathways important for energy
homeostasis, such as adaptive thermogenesis, mitochondrial biogenesis, fatty acid
oxidation
, and gluconeogenesis. PGC-1 interacts with and enhances the activity of
many nuclear receptors, like the peroxisome proliferator-activated receptors
(PPAR) alpha and gamma, TR, GR, ER-alpha, hepatocyte nuclear factor 4 (HNF4), as
well as nonreceptor transcription factors like the nuclear respiratory factor 1
(NRF1). A characteristic feature of PGC-1, not shared by other nuclear receptor
coactivators, is its C-terminal domain. It harbors sequence motifs typical of RNA
processing regulators and has been implicated in the regulation of pre-mRNA
splicing
.

response to cold ; GO:0009409
response to starvation ; GO:0042594
mitochondrion organization and biogenesis ; GO:0007005
fatty acid oxidation ; GO:0019395
gluconeogenesis ; GO:0006094
pre-mRNA splicing factor activity ; GO:0008248

Page 13920, bottom of the page

...This region includes a RNA recognition motif (RRM), which has been
implicated in the regulation of RNA processing...

RNA binding ; GO:0003723

Page 13921, last sentence of the first paragraph

Finally, consistent with the presence of nuclear localization signal
sequences, PERC is a nuclear protein.

nucleus ; GO:0005634

Second column, about half way down

The one nuclear receptor where PERC functioned as a potent coactivator
was ER-alpha.

estrogen receptor signaling pathway ; GO:0030520 [process]
ligand-dependent nuclear receptor transcription coactivator activity ; GO:0030374 [function]

p13922, end of the first paragraph

In conclusion, PERC interacts via two motifs, NR1 and NR2, with a
ligand-dependent conformation of the ER-alpha AF2 domain.

AF2 domain binding ; GO:0050682

Top of the second column

A fusion of PERC to the DBD of Gal4, which recruits PERC to a Gal4-responsive luciferase reporter, indeed activated transcription strongly.

positive regulation of transcription ; GO:0045941

p13923, top of first column

It potently enhances the ligand-dependent activity of ER-alpha, while
having only minimal effects on the activity of the related receptor ER-beta or
other nuclear receptors tested here.

ligand-dependent nuclear receptor transcription coactivator activity ; GO:0030374

p13924, second column, bottom of the page / p13925, top of page

PERC mRNA distribution is very similar to that of PGC-1. PGC-1 function in
heart, muscle, and liver may mediate physiological state signals to
tissue-specific transcriptional activation of proteins that regulate energy and
glucose homeostasis. For example, in response to exposure to cold, PGC-1
induces the expression of uncoupling proteins and stimulates energy expenditure
in brown fat and muscle, while in response to fasting, it stimulates
gluconeogenesis in liver.

cell glucose homeostasis ; GO:0001678
response to cold ; GO:0009409
response to starvation ; GO:0042594
gluconeogenesis ; GO:0006094

Previous exercise

Amelia Ireland