an example of endogenous retroviruses (KoRV)

Question 1

what endogenous retroviruses?

Answer 1

transmitted via germline

long ago, have integrated themselves as normal genetic elements in the chromosomal DNA

in humans, referred to as HERVs

Question 2

why was the koala population declining australia?

Answer 2

one factor was due to lymphomas and leukemias, mainly malignant

Question 3

describe the koala retrovirus (KoRV)

Answer 3

an endogenous retrovirus
- they always come from an exogenous transmission event
- they then, endogenizes itself into the chromosome
- from there, it can be transmitted thru the germline

KoRV was similar to the exogenous GALV from apes that caused leukemia
- the GALV made its way into the koala, and thru time, endogenized itself to stay there, now able to transmit via germ line; believed to be a decades old event

endogenization can be referred to as “colonization”

the original KoRV was termed KoRV-A

Question 4

describe the case study of koalas in US zoos and the implications of their findings

Answer 4

comparison between San Diego and Los Angeles

San Diego
- very limited outbreeding -> very low neoplastic disease

Los Angeles
- inclusion of Australian Koalas for breeding -> higher rates of neoplastic disease

KoRV-A was found in both San Diego and Los Angeles koalas

but some LA koalas had KoRV-B, a new isolate
- KoRV-B was transmitted thru breeding, thus, an exogenous retrovirus
- KoRV-B was linked to animals exhibiting higher degrees of neoplasia

no evidence pointing to a relationship between KoRV-A and lymphomas, leukemias, etc.

this example shows retroviral “endogenization” in real-time and is evidence that endogenous retroviruses are “doing something”

Question 5

what does current research say about endogenous retroviruses?

Answer 5

endogenous retroviruses are considered non-infectious, they aren’t making viral proteins because the sequences aren’t long enough

but there has been suggestive links between HERVs and lupus, an autoimmune disease due to the position of the HERV

Question 6

what is the conundrum regarding “ebola-free” patients?

Answer 6

there is still detectable viral RNA in “Ebola free” patients, specifically in the patients semen