FIG 4.

HSP genes engage in striking, heat shock-dependent cis and trans intergenic interactions. (A) HSP genes engage in frequent intra- and interchromosomal interactions in response to acute heat shock. (Top left) Normalized 3C interaction frequencies between the mid-ORF (+1550) region of HSP104 and the indicated regions within SSA2 under NHS and 10-min-HS conditions. (Top right) As described above, except 3C interactions were quantified between the HSP82 5′ end (+740) and indicated regions within HSP104. Analysis and symbols are the same as those described in the legend to Fig. 2A. Shown are means and SD; n = 2; qPCR = 4 for each primer combination. (Bottom) DNA sequence confirmation of novel joints formed between the HSP104 +1550 and SSA2 +855 TaqI sites and HSP82 +740 and HSP104 +1550 TaqI sites (indicated by silver and blue globes, respectively). (B) Matrix summary of intergenic contact frequencies between chromosomally linked HSP genes in 10-min-heat-shocked cells. Normalized interaction frequencies, determined as described for panel A, are presented for the indicated loci. n = 2; qPCR = 4 for each primer combination. (C) Interchromosomal interaction frequencies of representative HSP genes presented in pairwise combinations as described for panel B. HSP104, Chr. XII; HSP82, Chr. XVI; SSA4, Chr. V; HSP12, Chr. VI; SSA2, Chr. XII. (D) Intergenic contacts between the constitutively expressed BUD3 gene and heat shock-inducible HSP genes under the indicated conditions. Anchor primers corresponding to the 5′ end of HSP82 or mid-ORF of HSP104 (as indicated) were paired with primers located along the BUD3 coding and upstream regions. Shown are means and SD; n = 2; qPCR = 4.