The abundant latency-associated transcripts of herpes simplex virus type 1 are bound to polyribosomes in cultured neuronal cells and during latent infection in mouse trigeminal ganglia.
During herpes simplex virus type 1 (HSV-1) latency, limited viral transcription takes place. This transcription has been linked to the ability of the HSV-1 genome to reactivate and consists of abundant 2.0- and 1.5-kb collinear latency-associated transcripts (LATs), spanned by minor hybridizing RNA (mLAT). The 1.5-kb LAT is derived from the 2.0-kb LAT by splicing, and both transcripts contain two large overlapping open reading frames. The molecular action mechanisms of the latency-associated gene expression are unknown, and no HSV-1 latency-encoded proteins have been convincingly demonstrated. We have cloned the entire latency-associated transcriptionally active HSV-1 DNA fragment (10.4 kb) under control of a constitutive promoter and generated a neuronal cell line (NA4) stably transfected with the viral LAT's region. NA4 cells produced the 2.0- and the 1.5-kb LATs. Northern blotting and reverse transcription-PCR analysis of RNA from NA4 cells and from trigeminal ganglia of mice latently infected with HSV-1 revealed that the two abundant LAT species were present in the polyribosomal RNA fractions. After addition of EDTA, which causes dissociation of mRNA-ribosome complexes, both LATs could be detected only in subpolyribosomal, but not in polyribosomal fractions. These results show that (i) HSV-1 LATs are bound to polyribosomes during latency in vivo, as well as in neuronal cells in vitro, and therefore might be translated, and that (ii) the NA4 cell line is a suitable tool with which to look for HSV-1 latency-encoded gene products.
Goldenberg
D
D
Department of Neurology, Hadassah University Hospital, Jerusalem, Israel.
Mador
N
N
Ball
M J
MJ
Panet
A
A
Steiner
I
I
D000818:Animals; D006561:Herpes Simplex / Q000821:virology*; D018259:Herpesvirus 1, Human / Q000235:genetics* / Q000502:physiology; D006801:Humans; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000378:metabolism / Q000821:virology*; D011132:Polyribosomes / Q000821:virology*; D012367:RNA, Viral / Q000378:metabolism*; D012668:Trigeminal Ganglion / Q000378:metabolism / Q000821:virology*; D014407:Tumor Cells, Cultured; D017735:Virus Latency / Q000235:genetics*
D012367:RNA, Viral